Error: the type initializer for . . . threw an exception

Either the Microsoft DotNet Framework 2.0 and/or the Microsoft Runtime files are not present.  Do the following steps:

1) Install the following in the order the links are given - first the Framework, and then the Runtimes, if needed.
2) Install the Framework from
        http://www.microsoft.com/downloads/details.aspx?FamilyID=0856eacb-4362-4b0d-8edd-aab15c5e04f5&DisplayLang=en
3) If DF-Pro still gives the type initializer error, then install the Runtimes from:
        http://www.microsoft.com/downloads/details.aspx?FamilyID=32bc1bee-a3f9-4c13-9c99-220b62a191ee&DisplayLang=en