SuSE is a bi-arch distribution. Look in your package manager for 32 bit versions of the packages supplying these libaries. The 64 bit version also has 32 bit versions of many programs and the libraries they need. They are supplied in separate packages from the 64 bit versions. The 32bit libraries will be installed under /usr/lib, and the 64 bit in /usr/lib64.
If a SuSE package doesn't supply a needed library, a good place to look is at the http://rpm.pbone.net
website. In the advanced search, you can filter the search for your distro & version. For each package, the dependent files are listed and each one is a link to a package that can install it.
Another place to look at, especially for media related programs, is the Packman repository.
Starting with SuSE 10.3, you can select "Community Repositories" in YaST2 to easily add non-SuSE repositories such as Packman, NVidia, ATI, VLC, etal.
I wonder if you manually copied files for the plugin to /usr/lib/ instead of /usr/lib64?
If I remember correctly, with SuSE 10.2, the 32bit version of Firefox was installed by default. With 10.3, the 64 bit version was installed instead.
The "find" command can tell you whether you have an elf32 or elf64 library or program.