Are you talking about this article?
http://www.newsforge.com/article.pl?.../11/29/0254245

That one is over 4 years old! I don't want to badmouth Qtella but the Gnutella network and protocol has evolved quite a lot since then and Qtella is in no way up to par with LimeWire or other actively developed Gnutella clients. Actually, the Qtella project seems stale for at least the last 18 months
and the version you tried to compile isn't even one of the latest releases.

Anyways, your problem is that you have no C++ compiler installed, so you cannot compile Qtella from its sources. I would recommend looking for another alternative though.