Has an unmet dependancy of openssl-solibs. Not sure if this is a Std 6.0 b2.4 issue though.
I think there's a good chance it is down to b2.4. I deliberately regressed to b2.2 when I did the build, mainly because I was getting very strange dep problems every time I tried to install anything in b2.4.
Looking at /var/log/packages, a number of entries for packages that are on the system were missing, which I think is the main cause of the dep problem.
Does Firefox run ok if you force the install?