Could you be more specific about "non logic related problems"?
The following are som pretty basic things to try, i suspect that you already have tried the most or all of them.
1: Are you sure the problem is related to language and not the machines themselves? Try and check out all the DLL:s and other resources (like databases and stuff) that the program calls in the machines that go GPF and compare the versions to the other machines. Microsoft has a DB on their website where you can see witch DLL ships with what product. You should also search the KB for any information regarding the resources you use.
2: Install VB on one of the machines that go GPF and run the app in debug mode. Open an external debug file and print every step of the way to it, so the information will survive GPF. (Don't know if you can reroute the debug statement.)
3: Search your code for functions or subs that use dates and time. The problem could be related to use of hardcoded dateformats in US long date format (or other dateformats... ) that are being evaluated by built in functions like FormatDate or IsDate that evaluates against Windows system date format, thereby causing a conflict.
4: If the app connects to a DB, make sure both the DB-server and the app uses the same general country settings as this to may cause problems. If you have migrated the DB to MS SQL2K check for 'TS' statements sent to the server. (I know this particular statement can cause problems.)
5: Try to analyse the problems you get when running the app on a German machine to those you get when you run them on a Swedish. Most likely you don't have two separate problems, but one that shows itself in two different ways.
Basic stuff I know, but I hope it can at least provide you with some inspiration.
Good Luck
-Mats Hulten