Earlier today I spent some time installing the beta3-version of VSTS on a VPC-image. The entire experience reminded me of first few Biztalk 2004 installs I did: you come very close to finishing the installing, but it fails on the last step.
Some at Microsoft must have felt the pain this was causing. At MSDN-subscriber downloads there is a VPC-image available that contains the entire thing: Windows Server 2003, SQL Server and VSTS. At more than 2 gigabytes the download is sizeable but avoiding having to install all the different items makes it well worth the wait. It unpacks to about 9Gb.
If you intend to dive into all the VSTS-goodness Microsoft has been showing, you should seriously consider
avoiding a manual installation downloading this.