We have an exsisting Access 2003 database. My coworker was given a new computor and now when he trys to use the database he gets the following prompt: "The expression you entered has a function

You are probably missing a private library on the new computer, or have an incomplete installation of Access. Then simple functions like Date() or Trim() don't work, or user defined functions in a private library cannot be found. Your access project probably uses a special library that needs to be copied to the new computer, and it needs to be properly referenced by the Access project.
To see what libraries an Access project has referenced, open any code window (e.g. press Ctrl+G), and choose References from the Tools menu.
If a library is marked MISSING, click the Browse button, and locate the correct file for the library. The table below lists the files for the crucial libraries of your version of Access.
If the library is not even shown, you may need to re-register it. Click the Windows Start button, and choose Run. Enter regsvr32 followed by the full path of the library file. Include quotes if the file name contains spaces, e.g.:
regsvr32 "c:program filescommon filesmicrosoft shareddaodao360.dll"
Occasionally, the problem is not solved until you unregister the library and re-register it. Uncheck the missing library in Access. Close Access. Issue this command, and then the one above to re-register it:
regsvr32 -u "c:program filescommon filesmicrosoft shareddaodao360.dll"
Re-register it (as above). Open Access, and select the library reference again.