> Moved all this stuff from Win7 x64 to a virtual machine on Win XP x32.
> It seems to work there.
> Why in one system does not work, and in other works?

Evgeny is right - you mix 32-bit and 64-bit DLLs.

The Jaybird 2.1.6 supports only 32-bit platforms, the 64-bit ones are
supported by the upcoming Jaybird 2.2.

You can fetch the code from the CVS and build it yourself. It is pretty
stable, there are no critical issues left except that Jaybird 2.2
introduced some incompatibility with Firebird 1.5 on protocol level.
Will be fixed today or tomorrow. Then we want to fix the possible issues
in the pool code and that's it - build a release.

So, I think you can try already the version from CVS, when you're done
with porting your application, Jaybird 2.2 should be there already.

Alternatively you can use 32-bit Java, the main limitation is that you
can use up to 1.5 GB heap.

Roman