> Is is possible to use the 64-bit Firebird server with a 32-bit application?

Sure.

> If so, is it recommended? What are the pitfalls?

The only one is that a 32-bit application needs to use the 32-bit
Firebird client library and not the one from a 64-bit Firebird server
installation


--
With regards,
Thomas Steinmaurer
http://www.upscene.com/

Professional Tools and Services for Firebird
FB TraceManager, IB LogManager, Database Health Check, Tuning etc.