SBS 2003 Back completed with Errors

Can someone help me. My SBS have backup recently started to fail and d only clue i have in the event log is:
Application Popup:
Windows Delay write Failed- windows was unable to save all the data for the file
\Device\Windfs|\root\Server\back-up Exchange\Exchange Backup fr.bkf. the data has been lost.this error may be caused by failure of your computer hardware or your network connection. please try to save the file elsewhere.

Please Help if you have any clue of what is going on here.