I'd try the list, maybe someone can help you there.
http://lists.puredata.info/listinfo/pd-list

Hi, thought I'd post here even thought the thread is old before starting a new topic because my problem is exactly that as described here, though none of the suggestions have help and no one seems to have my exact error console output, which is as follows:

WARNING: Font family 'Courier' not found, using default (DejaVu Sans Mono)
tried ./gem.l_i386 and failed
tried /usr/lib/pd/extra/Gem/gem.l_i386 and failed
tried /usr/lib/puredata/extra/gem.l_i386 and failed
tried /home/digithree/pd-externals/gem.l_i386 and failed
tried /usr/local/lib/pd-externals/gem.l_i386 and failed
tried /usr/lib/puredata/extra/gem.l_i386 and failed
tried /usr/lib/pd/extra/gem.l_i386 and failed
tried ./gem.pd_linux and failed
tried /usr/lib/pd/extra/Gem/gem.pd_linux and failed
tried /usr/lib/puredata/extra/gem.pd_linux and failed
tried /home/digithree/pd-externals/gem.pd_linux and failed
tried /usr/local/lib/pd-externals/gem.pd_linux and failed
tried /usr/lib/puredata/extra/gem.pd_linux and failed
tried /usr/lib/pd/extra/gem.pd_linux and failed
tried ./gem/gem.l_i386 and failed
tried /usr/lib/pd/extra/Gem/gem/gem.l_i386 and failed
tried /usr/lib/puredata/extra/gem/gem.l_i386 and failed
tried /home/digithree/pd-externals/gem/gem.l_i386 and failed
tried /usr/local/lib/pd-externals/gem/gem.l_i386 and failed
tried /usr/lib/puredata/extra/gem/gem.l_i386 and failed
tried /usr/lib/pd/extra/gem/gem.l_i386 and failed
tried ./gem/gem.pd_linux and failed
tried /usr/lib/pd/extra/Gem/gem/gem.pd_linux and failed
tried /usr/lib/puredata/extra/gem/gem.pd_linux and failed
tried /home/digithree/pd-externals/gem/gem.pd_linux and failed
tried /usr/local/lib/pd-externals/gem/gem.pd_linux and failed
tried /usr/lib/puredata/extra/gem/gem.pd_linux and failed
tried /usr/lib/pd/extra/gem/gem.pd_linux and failed
gem: can't load library
input channels = 2, output channels = 2
audio buffer set to 25
opened input device name hw:0
configuring sound input...
Sample width set to 2 bytes
configuring sound output...
Sample width set to 2 bytes
tried but couldn't sync A/D/A

So I've added the word "gem" (with no quotes) to the Startup list, and the external library locations (whose paths can be seen in the above output) yet it doesn't work.

Any ideas? I've verified that both pd and gem are installed and at the lastest version. I'm using Ubuntu 11.10

Thanks