Based on data sheet, it is supported, and I have installed it before:
• 2.0 GHz Pentium 4 processor
• 1 GB RAM
• 1 GB available hard disk space
• Network card, connected to the network using TCP/IP
• SVGA (1024 x 768) display card
• Sound card and speakers (highly recommended)
• 17-inch or larger monitor (highly recommended)
• Keyboard with 10-key number pad
• Windows 7 (32-bit or WoW64), Vista Professional with SP2 (32-bit or WoW64), or Windows XP Professional with SP2
http://www.cisco.com/en/US/prod/collateral/voicesw/ps6789/ps7046/ps7282/data_sheet_c78-520987.html
You may need to look through the install log for clues on what is failing.
Chris