Howdy,
My girlfriend was having the same problem on my computer...
Assuming your friend knows to use the book on the end table in the corner of the living room of the apartment, but gets the "Save failed" error -- we found that it only saves properly when using my account log in. I'm the ***administrator***; so we figured that to save in this game (we have Windows XP, SP2) you MUST have administrative privelages...
Hope that helps.
-Michael