Always install using YAST and your original SuSE/Novell DVD

You did NOT mention to use YAST and your SuSE DVD as a source - using YAST checks dependencies and adds missing packages. That's how I use to install mozilla and firefox successfully. You also did NOT mention the exact SuSE version - this might help in case of persisting problems

Using full DVD from SuSE - there should be no serious problems of missing dependencies.

God bless

hans