The dreaded "Run Time Error 91"

[ttmac]

In our organisation there are several development teams developing software for different parts of the organisation and for different aspects of the organisations business. These applications are independent and might all be installed on one machine. After a recent release of the software for which we are responsible, problems have developed in another application.

Example:

Application 1 is up and running on the PC.

After release Applications2 is up and running, however application 1 is now exhibiting Run Time Error 91 at various points.

Application 1 is reinstalled and both applications are now working as expected and neither are generating the dreaded “Run Time Error 91”.

Application 1 is written in Visual Basic 5, Application 2 is written in Visual Basic 6 and both use Affinity Visual Toolkit for Windows. Windows systems mainly NT with XP being introduced.

I know it’s a very vague question, but what should we be looking for? This has me stumped.

Thanks for all assistance,

Tom

 

[ttmac]

For those interested, we have since solved the problem.

A dll file that is part of the Affinity Visual Toolkit for Windows, common to both applications, was overwritten by an older version of the same file during the installation of Application 2.

I think that Application 1 probably had an "On Error Resume Next" statement prior to the initialisation of the variable and it was never checked that the initialisation was successful. It was then, when the object was accessed that the Error 91 was raised.

We discovered the problem by having a clean install of application 1 and then installing application 2 one element at a time until we finally broke application 1.

Tom.