A common error seen within Windows XP, 2003, and 2000 occurs when connecting to a network shared drive or other network resources. The common error you could get when connecting to a shared network resource such as a networked is a permission denied error even though you know full well you have access to that drive and you have inputted your user name and password correctly. You may also see the error that the TCP/IP stack size is full in other programs.

To correct this all you need to do i s make a simple registry change to increase the stack size. Simply go to “Start-Run” and type “regedit” Once in the registry browse to “HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\ LanmanServer\Parameters” Then add a DWORD value and name it “IRPStackSize” exactly as you see it, since the value is case sensitive. Then right click on the value and select edit. Then put in a DECIMAL value form 11 to 50. Generally I use 25 its a nice number halfway to the max which gives me room to move up or down if need be. And now you should be set. For more info about the IRPStackSize visit Microsoft’s support page: http://support.microsoft.com/kb/285089

Now if you continue to get these errors and you have increased the stack size to about 30 and its still getting full or if you still cant connect to you shared network resource then you may want to explore the possibility of a malicious program running on your system, or that the service for the network resource is setup properly, and all the common stuff like firewalls and other permission settings.