Problem on Win 7 with an app compiled with LC 6.6 on Mac

[jbv at souslelogo.com]

Hi list,
I am using LC 6.6 build 4003 on Mac OSX 10.5.5 to compile
an app made years ago on LC 4.5.3 and constantly improved
over the years, with each new version of the app compiled with
a more recent version of LC...

And suddenly today, some of the users of this app in various
cities of the country seem to encounter problems on Win 7,
like app freeze or display going totally crazy...
My own tests on Win 7 don't show any problem, and these users
are hundreds of kilometers away and rather computer illiterate,
so they can't give me much details...
Other users of the Mac version of the same app compiled with
the same LC 6.6 don't seem to have any problem.

I have just re-compiled the app with an old LC 6.5.2 and am
waiting for feedback from my clients...

So far I don't see what else I could do... Has anybody faced a
similar problem ? Any wise tip about what to do ?

Thanks
jbv