I too have problems with GLSL. The effects are not applied, but I don't see any error message.
I had a working install with Ubuntu, but I switched to Arch because it's much faster to load, and I can install only exactly what I need. So I want to insist with my Arch install.
Here is the content of my mame.ini:
gl_glsl 1
gl_glsl_filter 1
glsl_shader_mame0 /home/arcade/.mame/crt/CRT
(I have a file name /home/arcade/.mame/crt/CRT.vsh that describes the effect.)
Since I had it working with Ubuntu I know that my hardware and the drivers allow to do it. What can I do to troubleshoot that? Is there a log somewhere where I can see what's going on?
Could it be possible that the sdlmame version from the Ubuntu repos is different enough from the Arch one that the settings are incompatible? I think the Arch version is much more recent.
Edit: with -verbose I got this output:
http://pastebin.com/WzTPRJpj