I get the same thing too. Figuring it was just because I didn't have OpenSLP installed, I went and got it (www.openslp.org), but I still get the same error.
Searching google, it appears the same error happens on slackware and mandrake, and according to bugzilla for mandrake, the problem was solved by removing the browse button.
So now, I haven't the slightest how to get it to work. Anyone?