Outlook Web vs MS Outlook

Hi all,

A junk mail folder in Outllook WEB is acting a liitle funny. When one of my users logs in from home and moves mail from the inbox to there Junk Mail folder they get a limit has been reached, contact the system administrator.

When The same person comes into the office and uses MS outlook he has no problems moving mail to his Junk mail folder. I dont see any quotas setup on the mail server. What do you think it could be. Mailbox size limits, to my knowlegde are not configured. His AD is set to use default.