Outlook 97 Error when Send/Receiving Email

"A message could not be delivered. Make sure ther is sufficient memory and disk space and the the message store is accessible and then try again"

 

Take a look at this MS KB article, it may help:
http://support.microsoft.com/support/kb/articles/q163/8/60.asp

You can also get this article by sending an E-mail with a subject of
"Q163860" (without the quotes) to mshelp@microsoft.com.

This problem is fixed in the "Internet Mail Enhancement Patch". You can find it here:
http://officeupdate.microsoft.com/downloadDetails/outlimep.htm

The link above has the outlimep.exe patch.