Autodesk Vault 2011 ASPX file failed to run...

[mevansrockit]

Geting the following error message when trying to install Autodesk Vault 2011 (Server) onto a Windows XP 32bit machine.

ASPX file failed to run at URL:http://localhost:80/TestASP/TestASPNet.aspx

Log file says -

Checking ASP Status - Accessing a static file through the http protocol has passed.  ASPX file failed to run at UL:http//localhost:80/TestASPNet.aspx.The remote server returned an error (500) Internal Server Error.

Launching http://localhost/TestASp/TestASPNet.aspx in IE returns the following -

Could not load file or assembly 'System.Web.RegularExpressions, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.

Any help greatly appreciated.