....but for starters you need the correct .NET Framework installed on the machine running the IIS.
Also you may need to setup an IIS application to run the web site in question.
As regards VWD: I myself have no experience with the 2008 versions, but trying to open a 2003 (.Net 1.1) project in a 2005 version will result in a mandatory project conversion which almost always goes bad. So...I you can, install and use the apropriate version of VWD for the project. A bad conversion will require you to hand-edit the faulty code.