Getting 'Invalid Taxonomy' error message, when I try to set up listing categories

Hi,

I have set up a new multisite installation at http://bizlister.net, with the first site being: http://bizlister.net/delaware

I have installed the Directory plug-in, and I'm now trying to configure it.

When I try to add listing categories, I get the following error message:

Invalid Taxonomy

Any ideas?

Thanks in advance,

Robert Ford