New problems building MythTV-0.27 for el6

Hi: I have MythTV Version v0.27-109-gcb744f8 under F18 x86_64 working well - thanks, Richard - and have tried to rebuild it for my laptop running Scientific Linux 6 with extras. I've given details earlier of the repos I needed for that, and it's been running well with a build I did using a slightly modified rpmfusion specfile and the git tarball about 3 weeks ago. Before that, rpmbuild --rebuild had succeeded under SL6 using the F18 SRPM. Now, rpmbuild --rebuild mythtv-0.27-3.fc18.src.rpm fails, probably because its BUILDROOT folder is mythtv-0.27-3.fc18.i386. This happens even if I rename the srpm to mythtv-0.27-3.el6.src.rpm I don't know where the fc18 tag is coming from, but it appears in the definition of RPM_BUILD_ROOT in config.ep So I've just tried mock instead. That says No Package found for lame-devel, although I have it installed and have just been able to download it (not within mock) from here: http://download1.rpmfusion.org/free/el/updates/6/i386/lame-devel-3.99.5-1... All rather puzzling. I'll perhaps try a new rebuild from git tarball. Any hints? Thanks, John P