I can't easily test the Mazurka plugins right now, as I'm using a 64-bit distro at the moment and they only come in 32-bit builds.
If you run sonic-visualiser from a command line, you might see some sort of useful error message (somewhere near the start of any debug or logging information it prints out). For example, if I install the 32-bit Mazurka plugins .so and run my 64-bit SV build, it says:
WARNING: FeatureExtractionPluginFactory::getPluginIdentifiers: Failed to load library /usr/local/lib/vamp/mazurka-plugins.so: /usr/local/lib/vamp/mazurka-plugins.so: wrong ELF class: ELFCLASS32
If you aren't getting any useful information out of Sonic Visualiser, you could try running vamp-simple-host instead (with the -l option to list installed plugins).