Running Gentoo, I understand the difficulty to provide support, though, it is a weird issue.

I am using Gentoo with GNOME 2.26 (but it crashed on 2.24 as well).
I am using PulseAudio on top of ALSA (as I understand it..)

Whenever I start workrave, all is fine.. when going to preferences->User Interface->Sounds and select any option other than 'no sound', workrave segfaults.

It doesn't say segfault on the command line, nor in .xsession-errors, but I see a segfault when running workrave with strace.

The problem is that I don't get any output, nowhere, so I am unable to determine why it crashes.. (To be clear, it crashes both on 'internal speaker' as 'use sound card').

Hope you can help me identify why this is happening.

Must have missed this one: I believe these problems have already been fixed in 1.9.1 (also see bugs #846, #864). Additional checks to avoid crashes when sound themes files are corrupt or files are missing have been added recently.