Somebody gave you the wrong information. vCenter 32-bit will only apply if you have have agents that need to be installed directly on vCenter, but most apps (if not all) still use API to communicate with vCenter, so 32-bit / 64-bit the apps have no knowledge of the architecture being used.
EMC backup doesn't talk to vCenter the server, it talks to vCenter the API which means it will not matter if you are running 32-bit or not... unless you are trying to install this on the vCenter server itself, which should not be required either.
What I suspect you are doing is installing EMC networker on *A* 32-bit machine, but you don't want to give a separate VM for this purpose, but the guidelines and recommendations will ALWAYS tell you to use a separate machine and never share the vCenter.. therefore if you install the EMC in *A* 32-bit VM with access (over the LAN) to vCenter that will satisfy your requirements. Use a separate server for this purpose do NOT install anything on vCenter, you are asking for trouble.
