Daniel introduced an exception bug in revision 1636 - and we didn't find it in time for release (though it was all too obvious to reproduce). 1649 is now released, and he checked in the change again - the new file dialog is now smart about subdirectories and namespaces (1650 if you are curious).

Also, the 1.0.1 installer is using a Windows Scripting Host (WSH) script to install three assemblies into the GAC and generate the help index. If your initial start tells you about a missing file, it might be that (a) scripting is disabled on your box or (b) your antivirus scanner has script blocking enabled. Sorry for the inconvenience, but simple batch files don't cut the mustard any more.