There is something wrong with the installation because the red dot in the bottom left hand corner of the template means that you are not connecting to the Gnutella network (which, as you have observed, is why the search button is not active). There are two possible explanations:

(a) you are on an educational or workplace LAN in the USA and, to protect the School/University/employer and you from legal action by the RIAA, the System Administration has barred connection to Gnutella, or

(b) the copy you downloaded was corrupted during transmission (not as uncommon as you might believe). You have to strip out everything with Limew in the label and trash it. Just using uninstall is not enough. Get thorough with Finder. Then download another copy and reinstall on a clean slate.

If the first is the answer, there is no legal solution. If the second does not work (I have had to try as many as five times to get a stable version), try another P2P package. Acquisition is LW based and working quite well at present.