[Serusers] error message during sendin instant message

Hi all: I'm trying hard to find solution to my problem but , I can't. If any one can help me. I use Windows Messenger Version 5.0 (5.0.0482) & Ser server RPMs: ser-0.8.12-0 ser-mysql-0.8.12-0 ser-debuginfo-0.8.12-0 I can register successfully using the windows messenger to the ser server and i can make voice session with other registered users. The problem occurs when sending an instant message to others registered users via Windows Messenger , the following error message appeared in the messenger: "The following message could not be delivered to all recipients" - I have another problem, when I sin in with Windows Messenger, I can detect the other users logged in before me but, they cannot detect me. by another word, the new logged one can detect the old logged users but, the opposite is not occur. - Tere is one attatchement compressed file contains The trafics of the Ethereal during problem Thanks for any one can help me.