A Google search turns up several possibilities, but if you're running
"Norton AntiVirus or another third-party application may have corrupted a
Registry entry on the computer you’re trying to connect to over a LAN"
http://www.smartcomputing.com/techsupport/detail.aspx?guid=06c6d72f9c3844818
64a02b680ca2d12&ErrorID=21575
****************************************************************************
***
Before building a new Main machine with XP Pro SP2 the network worked fine.
I have 3 machines all XP Pro, networked together using D-Link Router, Cable
Modem. My Main machine is a new build, which includes SP2. I used Network
Setup Wizard and then created a floppy containing a "netsetup.exe" file to
setup the other 2 machines, which do not have SP2.
I enabled sharing the drives of all the machines and shut off the firewalls.
I can access the 2 machines from my Main one, but I can't get access to my
Main XP SP2 machine from either one of the other 2 XP machines.
I get the following Error Message on both machines trying to access the
Main:

"C (or whatever drive or file I want) is not accessible.
You might not have permission to use this network resource.
Contact the administr
ator of this server to find out if
you have access permissions.

Not enough server storage is available to process this command."

           The NOSPIN Group is now accepting donations to help
          defer the costs of providing PCBUILD and our website.
           Visit http://freepctech.com to donate using PAYPAL