Has anyone tried installing ZCM on a 64 bit server? Are there any
gotcha's to watch out for?

The install documentation states the server install is compatible with

Windows Server 2003 SP1 Ent x86, x86-64
Windows Server 2003 SP1 Std x86, x86-64

SUSE Linux Enterprise Server 10 (SLES 10) on the 32-bit (x86) and 64-
bit (x86-64) architectures (Intel* and AMD* Opteron* processors)