Hello leaveone
Glad you posted this. I haven't had museek installed for a while, thinking it was an orphaned project. It seems to be very much alive in the fork called museek+.
The last time I installed using the deb package museek_050507 and ran into a problem with scons/libxml++ also. It's possible that the needed lib is named slightly differently than libxml++-1.0.so.1 (such as libxml++-1.0.so.0). Seem to remember digging a lib out of an older package of libxml++. Maybe even a symbolic link would work.
Have you checked this out?
http://www.museek-plus.org/wiki/MuseekOnDebian
I just installed using the apt-get method listed there and it worked very slick. Just be careful with musetup-gtk, installing that package needed some very major changes on my system. It's not needed as the command line musetup works just fine.
I'm running Mepis 3.4.3 (etch) so ymmv.