I had a problem accessing file shares from windows XP machines, it worked at first, but after some time the following error started to occur:
\\server\folder is not accessible. You might not have permission to use this network resource. Contact the administrator of this server to find out if you have access permissions.
Not enough server storage is available to process this command.
Examining Windows 7 computer event logs, I found following error in system logs:
Event ID: 2017
The server was unable to allocate from the system nonpaged pool because the server reached the configured limit for nonpaged pool allocations.
This led me to the solution:
Open regedit and change the following registry keys:
HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\LargeSystemCache
Value = 1
Value = 3