Yes, it looks like you're using 64-bit ActivePerl (as that's the only perl that wants to link to -lbufferoverflowU) with a 64-bit gcc compiler.
Using a 32-bit gcc compiler with 32-bit ActivePerl is fine, but using a 64-bit gcc compiler with 64-bit ActivePerl simply will *not* work in the same way.

The thing that's killing you is the fact that gcc doesn't have a bufferoverflowU library. You could work around that problem by copying one of the libraries in c:/strawberry/c/lib to c:/strawberry/c/lib/bufferoverflowU.a.
That would satisfy that dependency but I think you'll then striike other problems.

Options include:
1) Using Strawberry Perl instead of ActivePerl;
2) Using ActivePerl with one of the freely available MS compilers;
3) Installing ExtUtils::FakeConfig into ActivePerl - which *will* enable you to use 64-bit gcc with 64-bit ActivePerl.

I've done 3) with ActivePerl 5.10.0 (build 1005) and it works fairly well. Sometimes I can't build distros that use Module::Build ('perl build.pl') instead of dmake ('perl Makefile.PL') - for reasons that I've yet to uncover.
And I had to additionally create a libperl510.a - which, in your case, would be libperl514.a .

Cheers,
Rob