ASP.Net - Server Application Unavailable - Urgent

Hi,

Our Web server runs Windows 2003 Server, IIS6.0, ASP.Net 2.0. We randomly
get "Server Application Unavailable" error.

The event log says
"Failed to execute request because the App-Domain could not be created.
Error: 0x8007000e Not enough storage is available to complete this operation."

Can anybody help to resolve the issue.

Thanks.