Thread:Project:Support desk/Scribunto / Lua error: Cannot create process./reply (22)

Could you point me to the file you're trying to import? Would you be willing to try the MediaWiki 1.22rc1 that I just put out or (at least) MW 1.21?

There have been a few updates in Scribunto. Since MW 1.20 is about to go out of maintenance, I think it is worth your while to upgrade.