I'm having the same problem with various programs at random times and with increasing frequency (and annoyance). Microsoft recommended reinstalling. Did that, sort of. Didn't help. Also the problem is not just with Microsoft programs. Anyway I did try Doris's idea (thank you) of checking permissions in the Applications folder, and added myself with read and write privileges for one of the offending programs (Word). We'll see if that works. What always works for me is opening the program a second or sometimes third time. I get the "you do not have permission error", the program crashes (send the error report to Apple with "I'm thinking of buying a PC" in the comments section), and then reopen the program and I'm fine until the next time.

I'm having the same problem. I get the "you don't have permission" error and then the application crashes. I send the report in to Apple and then reopen the application. It usually opens on the second or third attempt. Annoying, not fatal.