Hubert,
As a follow up, I uninstalled SC1, ensured all files & folders were deleted, reinstalled, and then patched with the download from this site. Again, it worked insitially, but after powering down & back up, I get the same error. SC2, while in a different folder, is the only thing I can think of, since SC1 worked fine for the longest even with community mods until I installed SC2. I suppose uninstalling SC2 is the next try, since honestly if I must choose between the two, I'd choose SC1.
R/John