Quartus 9.1 SP2 install problem (windows)

We are trying to update to SP2. This is a Windows 2003 server box with an NTFS file system. The install begins running and receives an error message in a dialog box.

Feature Transfer Error

Feature: Quartus II

Component: Program Quartus Files

File C:\tools\altera\9.1\quartus\license.txt

Error: Access is denied

So far I have tried the following:

1. log onto a different user (both had admin rights on the machine)

2. Re-downloaded the SP2 install file

3. Deleted the existing license.txt file

All have yielded the same error. Any advice for us ???