automatic reply failed to lock file error

version 3.31 on fedora 6

I need to set an automatic reply for an email user, so I go into edit mail and ftp users and fill in the information and hit save, but all I get is this error "Failed to lock file /etc/webmin/virtual-server/userdb" I tried last night and today and it times out after about 5 minutes, in fact I think it even said "after 5 minutes below the error"