> Which dlls are required for embedded connection in 64 bit system?

As Evgeny pointed out, you can use 32-bit DLLs with 32-bit FB, but also
your Java should be 32-bit. If you want/need to use 64-bit Firebird or
Java, you can take the version from the CVS, it supports also 64-bit FB
(there are appropriate DLLs there and JDBC driver knows which to load).

Roman