OK, time for me to reach for my "I am lame" hat...
Sonnet lib v294, only things in Q3 folder are quake3 and baseq3 folder and that has 9 pk3 files copied over from a PC install of the full game (which works). Folder is named "Quake III" (with a space). I start quake3 with no command line options and it craps out with a storage exception. Sonnet has 192Mb, rest of Amiga has about 132Mb in it. 640x480 LE video mode works fine.
What am I missing?