Do add-in's have to be compiled for 64 bit versions and 32bit versions? We will have clients, some with XP64 and some (most) with XP32.

Also, what about the servers. Our primary PDM servers will all be running Windows Server 2003 x64. We have an older server I thought about using as a test server but it has windows Server 2003 32bit. Would there be problem testing on it and going back and forth.