Correct Password is Rejected

Users who's passwords have expired or haven't been into our BSP application in more then 30 days are being asked to reset their passwords. But when they try and chnage the password using their expired password they get this error message: "You have incorrectly entered the current password that is allowed. Enter it again". This is occuring on the system changepw.htm page. I have found this message in OTR repository but can't find where it is being raised. Does anybody know what might be causing this problem or where the error is being raised. The only thing that has recently changed in our system is we have been applying some Support Packs.