It's not a 32-bit vs 64-bit issue. (Lots of people use the 64-bit version fine and you can't have installed the 32-bit version on the same machine you tried the 64-bit version on. It's likely to be something on the 64-bit machine that is conflicting.)
The information in these FAQs should help track down what is causing the freeze:
[ul][li]Crash, exit or high CPU usage when viewing certain directories[/li]
[li]Crash, exit or high CPU usage when right-clicking certain files[/li]
[li]General slowdown or instability investigation steps[/li][/ul]