Problem with a Crystal Report 8.5 customized dll

Hi,

I have created a customized dll for Crystal Report 8.5. I made a package and distribute it to several PC. I can run Crystal report with the dll function without any problem. But, I cannot run same dll on one PC that I have recently upgraded the from NT4 to MS Win 2000 with SP3. I install the package to that PC and register the DLL with success message. When I run the crystal report from the VB6 application the dll does not function at all. I do not understand it works on one pc with same setting and it does not work on other pc. Where do you think the problem is?

Thanks,

Naci