Open notepad and paste this in it:
<configuration>
<startup>
<!-- BETA 1 <supportedruntime version="v2.0.40607"> -->
<!-- BETA 2 <supportedruntime version="v2.0.50215"> -->
<!-- RELEASE CANDIDATE -->
<supportedruntime version="v2.0.50727">
</startup>
</configuration>
Save the file to this location:
C:\Program Files\NDoc 1.3\bin\net\1.1\NdocGui.exe.config
(or wherever you installed ndoc)
Look here for updates:
http://ndoc.sourceforge.net/