Unisys model uds25 has a error message "invalid engire"

A critical firmware error has occurred.
This type of error can be caused by invalid
print commands, corrupt data, or invalid
firmware operations.
NOTE In many cases, turning the
power off and then on will
permanently clear most 49 errors.
In some instances, electrical noise in the
cable can corrupt data during transmission to
the device. Other causes include poor-quality
USB cables, poor connections, or specific
software programs.
1) Upgrade the firmware.
2) If the message persists:
Turn the MFP off.
Remove the DIMM.
Remove any installed EIO devices.
Turn the device on.
If the error message disappears,
reinstall the DIMM and EIO
devices individually, making sure
to turn the device power off and
then on again as you install each
device.
g. Replace the component that
caused the error message.

"the printing operation has been aborted.
The issue can be caused by a firmware error, invalid print commands, corrupt data, invalid operations, poor quality parallel cables, poor connections or specific applications.

Action :

1> Press Cancel Job to clear the print job from the printer memory.
2> Turn the printer off and then on to clear the error message.
3> Try printing a job from a different software program. If the job prints, go back to the first program and try printing a different file. If the message appears only with a certain software program or print job, contact the software vendor for assistance.

If the above action does not solve the issue, contact HP or authorized service provider."

Critical firmware error. Can be caused by invalid print commands, corrupt data, invalid operations or even electrical noise in the cable.

Turn off the printer, then turn it on.
Press Stop to clear the print job from memory.
Turn off and back on.
Print a document from a different software program.
If that document prints, go back to the first program that failed and print a different file.
If the error comes back, that file is corrupt.
If the message persists with different programs and print jobs have the formatter replaced.

Error 49.xxxx - this type of error can be caused by invalid print comands, corrupt data or invalid operation...try this steps to resolve... :
1 Turn the MFP off, and then turn the
MFP on.
2 Upgrade the firmware.
3 Try printing a job from a different
software program. If the job prints, go
back to the first program and try
printing a different file. If the message
appears only with a certain software
program or print job, contact the
software vendor for assistance.
4 If the message persists when using
different software programs and
attempting specific print jobs,
disconnect all of the cables that
connect the MFP to the network or a
computer.
5 Turn the MFP off.
6 Remove all DIMMs and flash-memory
cards. Do not remove the firmware
memory card that is in slot 1.
7 Remove all of the EIO devices.
8 Turn the MFP on.
9 If the error message disappears,
reinstall each DIMM, flash-memory
card, and EIO device individually,
making sure to turn the MFP power off
and then on again as you install each
device.
10 Replace the component that caused
the error message.
11 If the error persists, replace the
formatter

Control Panel Message:
49.XX.XX
PRINTER ERROR
To continue
turn off then on

Description:
A critical firmware error has occurred that
caused the processor on the formatter to
abort operation. This type of error can be
caused by invalid print commands, corrupt
data, or invalid operations. In some cases,
electrical noise in the cable can corrupt
data during transmission to the printer.
Other causes include poor-quality parallel
cables, poor-connections, or home-grown
programs. On rare occasions, the formatter
is at fault, which is usually indicated by a 79 Service Error.

Recommended Action:
1. Turn the printer off then on.
2. Press Stop to clear the print job from
the printer memory.
3. Turn the printer off then on.
4. Try printing a job from a different
software program. If the job prints, go
back to the first program and try
printing a different file. If the message
displays only with a certain software
program or print job, contact the
software vendor for assistance.
5. If the message persists with different
software programs and print jobs,
disconnect all of the cables to the
printer that connect it to the network or
computer.
6. Turn the printer off.
7. Remove all memory DIMMs or thirdparty
DIMMs from the printer. (Do not
remove the firmware DIMM.)
8. Remove all EIO devices from the
printer.
9. Turn the printer on.
10. If the error no longer exists, install
each DIMM and EIO device one at a
time, making sure to turn the printer
off and on again as you install each
device.
11. Replace a DIMM or EIO device if you
determine that it causes the error.
12. Remember to reconnect all of the
cables that connect the printer to the
network or computer.
13. If the error persists, upgrade the
firmware compact flash card. See
Installing a flash memory card
on page 113.
14. Replace the formatter and calibrate
the printer. See Full Calibrate Now
on page 521.

From the service manual:

A critical firmware error has occurred that caused the processor on the formatter to abort the operation.
This type of error can be caused by invalid print commands, corrupt data, or invalid operations.
In some instances, electrical noise in the cable can corrupt data during transmission to the printer. Other causes include poor quality parallel cables, poor connections, or specific software programs.
Sometimes, the formatter itself is at fault, which is usually indicated by a 79 Service Error.

Recommended action:

1 Press CANCEL JOB to clear the print job from the printer memory.
2 Turn the printer off and then on.
3 Go to www.hp.com/go/lj4300_software, Select Download Drivers and Software. Check for the latest firmware image version at the bottom of the page. If this firmware image is newer than the one installed on the printer and the printer can receive a firmware update, download the newer firmware
upgrade. Not all HP LaserJet 4200/4300 printers can receive firmware upgrades.
4 Try printing a job from a different software program. If the job prints, go back to the first program and try printing a different file. If the message appears only with a certain software program or print job, contact the software vendor for assistance.
5 If the message persists when using different software programs and attempting specific print jobs,
disconnect all cables that connect the printer to the network or a computer.
6 Turn the printer off.
7 Remove all memory DIMMs or thirdparty DIMMs from the printer. (Do not remove the firmware DIMM in slot J1.)
8 Remove all of the EIO devices from the printer.

After performing the actions above, procede with the following:
1 Turn the printer on.
2 If the error message disappears, reinstall each DIMM and EIO device individually, making sure to turn the printer power off and then on again as you install each device.
3 Replace the DIMM or EIO device that caused the error message.
4 Remember to reconnect all of the cables that connect the printer to the network or computer.
5 If this error message persists, replace the firmware DIMM.
6 Replace the formatter assembly.

Try this

Turn the printer off hold down the menu button turn the printer back on while continuing to hold down the the menu, when you get a green light your ready to print

49.XXXX PRINTER ERROR To continue turn the printer off then on Description The printing operation has been aborted. The issue can be caused by a firmware error, invalid print commands, corrupt data, invalid operations, poor quality parallel cables, poor connections or specific applications. Action

1. Press Cancel Job to clear the print job from the printer memory.
2. Turn the printer off and then on to clear the error message.
3. Try printing a job from a different software program. If the job prints, go back to the first program and try printing a different file. If the message appears only with a certain software program or print job, contact the software vendor for assistance.
4. If the above action does not solve the issue, contact HP or authorized service provider.

he printing operation has been aborted.
The issue can be caused by a firmware error, invalid print commands, corrupt data, invalid operations, poor quality parallel cables, poor connections or specific applications.

Action :

1> Press Cancel Job to clear the print job from the printer memory.
2> Turn the printer off and then on to clear the error message.
3> Try printing a job from a different software program. If the job prints, go back to the first program and try printing a different file. If the message appears only with a certain software program or print job,.

check the Technical Support Team for this machine My guess is the drum is on its way out - or some other replaceable control item but they will know.