[tiermann]

If you want to convert a cab into an OEM then you use import. If you just want the cab file itself to be there in \Windows then you drag and drop.

Importing not only adds files but registry settings. It's not perfect so you'll have to look through each of them to make sure there are no errors. That's most likely where the buildOS error is coming from. You may want to check your temp/log.txt to see the exact rgu and line # that's giving you problems.

As for write protected.. if your tools directory is on portable media, make sure write protection (or read only) is off. Cab files will need to be extracted to a temp folder to be added.