The pogramm works fine on windows2000, but it doesn't on winXP(SP2)

It can't load the postgreSQL plugin . I've tried different paths aso.
It's realy interesting, if i start the program from network directories, it works also on XP.
Where is the difference between win2k and XP (the handling of pathnames)?

Does somebody knows an answer? Or even a workaround?

Thanks - jmh

I use QT4.1