I'm posting this here because all I'm getting is the runaround from Autodesk, and I truly thing something in their auth codes database is broken. I've got a network install image for 28 standalone seats of LDT2005 and just installed another new computer. Up until now there have been no problems. With the new computer, the install goes completely normal, (running XP SP1), but when it automatically checks for authorization via the Internet it comes back as failed. So I call in the ph. no., and they tell me the request code is invalid. So I uninstall, completely clean away all the Autodesk folders and registry info, re-install, and get a new request code. 'Same thing happens. I call again - same response - invalid request code. The serial number is correct, and even when I send the auto-generated xml files to the auth email address, or cut and paste, I keep getting the same response - check to be sure I didn't type something wrong. I didn't type ANYTHING!! - these are all cut and paste or direct emails of the request codes automatically generated!! I even got the same response when filing a support request via subscription - please be sure you have correctly typed in the info. Nothing was typed!!! It was all direct from AutoCAD!! Installs have been working fine until now - why does Autodesk keep telling me LDT is generating invalid request codes, and how can I get this resolved??? Thanks for any suggestions - John