I'm running hudson with "java -jar hudson.war" on Debian/Lenny and installed the
xnvc plugin.

When I click the help icon for either "Command line" or "Base display number" I
only see:

-----------------8<--------------------------------
Status Code: 404
Exception:
Stacktrace:

(none)

Generated by Winstone Servlet Engine v0.9.10 at Sun Aug 16 22:27:19 CEST 2009
-----------------8<--------------------------------

When going to ~/.hudson/plugins/xvnc I see the help pages files,
help-baseDisplayNumber.html and help-commandline.html .