Old School Failure on SUBST command in XP64

I ran into an odd issue yesterday that I thought I would share.  It is something I've done literally hundreds of times, but yesterday and today it would not work.  I was testing a new deployment of AutoCAD Architecture 2011 and kept running into Error 1926 when installing from a spoofed network drive, you know the kind you create by dropping into DOS and running the SUBST command. 

I searched and searched for answers on the Autodesk NG and google to no avail.  The only thing I found was related to VISTA...but I was running XP64.  After setting, verifying, and resetting permissions on the folders and drives, I abandoned using subst.  It seems that using SUBST to create drive letters in Windows XP64 created a permissions issue with the Windows MSI installer.  Thankfully, the problem went away when I created the drive letter using NET USE.

So if you run into this problem, try mapping the drive letter using NET USE with the syntax of (Note-remove extra space before machine name, inserted here to prevent hyperlinking):

\\ MACHINENAME\SHARE

For more info on NET USE try this link: http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/net_use.mspx?mfr=true