Somehow or another we have a project that runs on a dev machine, where both 2.0 and 2.5 is required. The bin directory has only the 2.5 versions of the ORM and DQE dlls.

When we push it to the server, I get an error that it can't find the 2.0 ORM dlls. Can someone provide an explanation on why it is working on the dev machine, but not on a server?

We have never installed LLBLGEN on the server, merely copying the needed dlls in each project's bin directory.

Is is a registry setting or something? Would placing the 2.0 and 2.5 versions in the GAC be the way to go on the server?

Thanks.

Check if every project in the app is actually referencing the correct assembly. Don't place the runtimes in the GAC, it's not necessary and it will give you headaches when applying fixes. Check also if you have referenced the correct ormsupportclasses and also: check the web.config file to see if you don't refer to a runtime lib version older than v2.5