kara,
Please check the following article:
This article is about SharePoint Portal Server. But it will help your debugging.
Cause:
This problem may occur in situations where the server is under a heavy load. For example, this problem may occur if the portal contains more than 100 subsites, and one or more Web pages that are contained in each of the 100 subsites is accessed at the same time.
asp.net Chat http://cutesoft.net/ASP.NET+Chat/default.aspx
Web Messenger: http://cutesoft.net/Web-Messenger/default.aspx
asp.net wysiwyg editor: http://cutesoft.net/ASP.NET+WYSIWYG+Editor/default.aspx
asp wysiwyg html editor: http://cutesoft.net/ASP
asp.net Image Gallery: http://cutesoft.net/ASP.NET+Image+Gallery/default.aspx
Live Support: http://cutesoft.net/live-support/default.aspx