The spec file is looking ok for me.
A little thing is missing in the changelog section.
it have to be
* Thu Aug 30 2012 Lord Spectre <lord dot spectre at hotmail dot it> 1.5.1-1pclos2012
- Updated to version 1.5.1
i know the people which packaged it before didn't do it but this is the current format for this entry.
and a little note that this is only a 32bit package would be also nice