Hi Wojciech, Bruce,
Don't know if this is relevant, but I've definitely seen conflicts with Perl interpreters when trying to develop Epics applications on Windows, as Epics builds need Perl with Strawberry recommended for Windows.
I've been able to have both C:\Strawberry and C:\Demeter as long as C:\Strawberry is not in the normal PATH, and only gets put in the PATH for Epics work.