Problems with different Versions of Win NT

Hello!

I compiled PostgreSQL 6.5 under Windows NT 4.0 with service
pack 3. There - apart from some strange errors - everything seems
to work all right.
On the same computer I installed Windows NT 4.0 with service
pack 4. Then I compiled PostgreSQL 6.5 exactly in the same way,
but unfortunately this time it does not work. For instance, if I try to
do the regression tests, the systems tells me <destroying old
regression database...>, but then it hangs up. And this was not the
only problem. While compiling the system (here Win NT!) crashed
several times seriously.
So my question is: Is there any know problem concerning different
service packs for Win NT? Any hints would be appreciated.
Thank you very much in advance.

Ruediger A Martin