Firefox 3.5 Mac Os X segmentation fault

To my surprise, my new Firefox 3.5 on Mac OS X suddently stopped working.

/Applications/Firefox-3.5.app/Contents/MacOS $ ./firefox
./run-mozilla.sh: line 399: 2036 Segmentation fault "$prog" ${1+"$@"}

I don't remember the exact version, but I downloaded Firefox 3.5.2 again and it has worked since. I haven't seen this reported elsewhere by a web search.