I just found out about Songsmith so I have not installed it yet. But I do have an idea. Have you checked the Event Viewer to find specific errors? I found this while looking for a version of WPF that could be installed aside from all unnecessary
parts of .NET since you have it already.
http://windowsclient.net/downloads/. If that doesnt work, at least you will have another source using those sites to help solve your issue.
I'm having the same problem on Vista Basic SP2. I had .NET 1.5, 3.5 and even installed 4 and still got the error. I finally removed all versions and attempted to install 3.0 from the link that Songsmith creates. However, the installer stops
and says I must use the programs and features in control panel to configure it. I go into programs and features in control panel and check all boxes under .NET 3.0 and still Songsmith says I need .NET 3.0.