Unable to install Vista on Leopard

I'm trying to install Parallels and then Vista, but can't get past the early stages. I seem to have installed Parallels OK, and in the final stages I chose Vista as my default Guest OS, insert the DVD, and then clicked on install (to install Vista). I choose the Windows Installation mode (have tried with both), I enter the registration number, I click on start and then get the splash screen which says "Windows Vista" and "Stopped". If I click anywhere I get the beachball for several minutes before trying again. Have tried eight times now.

I'm running Mac OS X Leopard on a fully pimped-up Mac Pro (2x3 Ghz Quad-Core Intel Xeon with 16gb RAM). My Parallels box says "Now Supports Windows Vista". And I'm installing an authentic copy of Vista Ultimate. Have even tried both 32 bit and 64 bit versions of Vista with the same results.

Any ideas? Thanks in advance!

 

It's alright

I did a full reinstall of Parallels, and it works now. Very strange.