Hudson ignored CVS updates

In a setup where Hudson polls CVS for updates I ended up in a situation where newly added directories were ignored, and thus Hudson did not trigger a re-build of the product.

The Hudson "CVS Polling Log" looked like this:

[workspace] $ cvs -q -z0 -n update -PdC -D "Wednesday, March 2, 2011 3:51:38 PM UTC"
cvs update: New directory `.....' -- ignored

The fix was to delete everything inside the "workspace" directory. On the next Hudson run, it performed a complete cvs checkout and that included all changes.