Outlook error shuts down program

Hello,

I have the following error from one of the office computers

"There was a problem ready one or more of your reminders. Some reminders
may not appear. The file \\Evrsvr\Personal\Pam\Outlook\backup.pst could
not be accessed".

After this message occurs they are kicked out of Business Vision. They just
restart the app and it works fine for another couple of hours.The for no
reason it doews it again. There are 12 stations and was only happening on
the one computer until last night a second computer got the same error and
kicked thm out of Business vision.

I have tried the switch /cleanreminder and that does not seem to fix this
issue any suggestions or help would be great thanks

Stan