Windows Server 2003 logon problem

I have just created an OU for two users as well as Group Policy which are of mandatory roaming profiles. When trying to logon I am now getting the error message that says roaming mandatory profile is not available or there are network problems. Can anyone provide at least a clue as to what the problem might be I thought maybe if I changed the perissions to accept all log ons that would work but it did not.What am I doing wrong?