I have an odd problem for which I'm sure there is a very simple solution.  I back up AC to a  "server" in my office.  This is essentially a home server and I only use it for back-ups and not a true server.  It is networked.  AC will back-up to the chose file location on this server if I do a manual backup under the backup utility.  But when I have it set for auto backup, it will never write to the file location claiming lack of access.
I thought this may be do to some log on issues but if that was the case, the manual backup shouldn't work either.  Correct?  
Any ideas?