Hello Daniel,
I'm sorry your wife is having trouble saving files. What you've described sounds strange, but let's go over a few things and see what we can do to help.
First, could I trouble you to please capture a screenshot of the actual error message on screen? Or at least maybe you could copy-paste the error message text? It's best if we know the exact error before making assumptions about it.
That said, I have seen system errors that talk about "permanent version storage". Here's a
screenshot of this error that I found via Google. Is that the exact error you or your wife encounter? We have actually discussed
this problem here on the Nisus forums too. It seems to occur if either:
1. The document is being saved on certain kinds of remote or detachable drives. -or-
2. The document is renamed or moved externally (eg: in the Finder) while it is open for editing in Nisus.
Do either of these situations apply?