I've created a custom element and compiled 32/64 bit version DLLs. It runs fine on my machine (with the newest version of OpenSees 2.5.0), but when I pass along the DLL file it doesn't run on another machine (also running 2.5.0 with the same 32/64 architecture).
The second machine fails to find the class file when running the Tcl script and returns "ERROR -- element of type ______ not known".
I've tested this on 3 machines now and haven't had any luck yet.
EDIT: Before you ask it, I did updated to the latest developer source code before building the DLL. Is it necessary to have the developer source code on the second machine as well? I wouldn't think so.