Access violation in CreateForm

We have a Delphi 3 application that uses QR. Normally program is 
quite happy but we have recently had several instances on WinNT and 
now one on Win XP where the following happens.

1) Users use the program quite happily for several weeks.

2) Suddenly, with no apparent reason, it stops working. They report 
Access Violation in <application name> before the main screen is 
displayed.

Using the old-fashioned technique of creating a diagnostic version of 
the program, I can trace the failure to the "CreateForm" call for the 
first module that contains a QR report in the project source.

I then created another diagnostic version that moved all of the QR 
module "CreateForm"s further down the list and the diagnostics showed 
that the program failed whilst creating exactly the same module.

I have not overridden the Create method for this class.

In the case of the NT 4 PCs, we can reset them to their original 
state and the application runs again. This is not an option in the 
case of the XP PC.

Any ideas?

Best wishes

Jeff Gallant