The program keeps freezing on my Win 7 64 bit system - is the program coded to work wit 64 bit systems? It works fine on my 32 bit system (XP Pro)

I've throughly tested the program over the last 1 hour and 40 mins on two systems; a Win 7 Ultimate 64 bit system (up to date with patches) and a Win XP Pro 32 bit system with SP3. so far it's frozen several times using the 64 bit sstem and never frozen on the 32 bit system, which would lead me to suspect this program hasn't been optimized for 64 bit systems yet. Would the developer comment on this please. thank you.