There was no need to post this twice. Patience is a virtue.

Credit to MVP Hans-Georg Michna - This error indicates that you are falling
foul of the IRPStackSize bug. The problem is on the machine you are
attempting to connect to, not the machine where you see the error message.
On the computer you are attempting to connect to, check the event viewer
for an event ID 2011.

Usual fix : You need to fix a parameter called IRPStackSize

On the computer you are attempting to connect to, Set the IRPStackSize back
to the default (15 ). Perform the following steps:

 1. Start regedit.
 2. Navigate to
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanserver\parameters.
 3. Double-click IRPStackSize (or if this registry setting doesn't exist,
create it with type DWORD and ensure the case is correct).
 4. Change the base to decimal, set the value to 15, and click OK.
 5. Reboot the computer.

Norton AV is usual suspect for breaking it. There's a KB article about this,
too:

Antivirus Software May Cause Event ID 2011 (Q177078)
http://support.microsoft.com/default.aspx?scid=kb;EN-US;177078

Malke