Aspnet_wp.exe Crashing Intermittently

I have an application which is providing printing facility using a custom hardware interface device.
Whenever a print is required user punches in his ID number into the hardware device, and hence an underlying application gets the event and it calls a managed DLL, which inturn calls the Reporting services webservice on the same server. Problem starts after some days (typically after 2 -3 days), when the server response becomes slow and the aspnet_wp.exe restarts every now and then and after this sequence of happening, finally it crashes with some event in application in event log which reads:
The server was unable to allocate from the system nonpaged
pool because the pool was empty.

Also many times the applications log file reads :
There is an error in XML document (1, 948).
I think this error starts when the aspnet_wp.exe is restarting, but I am not sure.

The server operating system is Windows 2000 SP-4, MS SQL Server 2000 Standard Edition SP-4, MS Reporting Services 2000 Standard SP-2 with .Net Framework v1.1
The Server is running many applications apart from the ones listed above and there is a moderate usage of TCP/IP sockets for communicating with certain hardware devices.
Please help me out!