I don't know what the problem is

check the toner to make sure that you remove the plastic strip.

Do a system restore to one week ago.

Google the game for instructions.

try to reset the the black printhead , and clean the it

Restart both your printer and your computer. It might finish the print job after you restart the printer and yes it will block any other print jobs.

Go into your control pannel and open up "Printers". Right click on the printer you are using and select "Properties". In the box that comes up choose "advanced"
In the middle of the menu box there should be "Spool print documents so program finishes printing faster" below it is "Print directly to the printer"
Change the option to Print directly and then press Apply at the bottom, this will get rid of the "Serial Job Number" that comes up before printing. :o)

Turn the unit off. Remove the cartridge and shake it back and forth. Ten place it and turn the unit back on. Also you can reset the counter on the cartridge, go to UNI KIT and look under Brother TN 110 refill support. These people sell refills. The ink you get with he printer is minimal. Also turning the printer off and back on will help with resetting. I found that there is plenty of toner left when the warning comes on.

In your printer driver Cd there are three type of hp laserjet 1200 installations you can find out. pcl5/pcl-6 /and ps versions. Try to print your bill form through these three driver sioftwares.And moreover i want to know that what software format you are using in your bill printing ?.

Usually if you see the page in the Publisher window is already landscape, it will go landscape in the Printpreview and also in the print out. I just try to imagine what is your problem.
If I am not mistaken, this is what you did:
You have two "small" pages (maybe A5??) and you want to print it in one page of A4. Of course the A4 should be landscape.
Publisher does not have the facility to set 2 pages A5 in one A4 like in Microsoft Word.
The easiest way is just create a new page with A4, then copy the 2 pages (or you called it flyers) and paste it in that A4 landscape page.
Publisher can do print 2 pages A5 in one sheet A4 but the arrangement is as booklet. You can see the choices in File --> Page Setup --> tab "Layout" --> scroll the Publication type.
I do print 2 pages A5 in one sheet with many variations using addition software named "Clickbook".
Let me know if I m wrong in interpret your problem.