I'm running Windows 7 64bit (Could that be a problem?) and Strawberry Perl 5.10.1.3

I'm running Windows Vista 64 bit with both 32-bit and 64-bit builds of Strawberry Perl, and there's no problem.
I guess there could be some Windows7-specific issue involved ... but I've not heard of any such thing.

The compilers you're using are 32-bit compilers, which should be fine as long as your build of Strawberry Perl is also 32-bit. I don't think Strawberry Perl even provides a 64-bit build of perl 5.10.
Anyway, just check that perl -V:archname reports MSWin32-x86-multi-thread, not MSWin32-x64-multi-thread

Can't really think of anything else ...

Cheers,
Rob