Crash during CaScadeS installation, and usage problems (with workaround)

Attempting to install CaScadeS 0.2.2 on FizzillaCFM/2002101303 on Mac OS 
X 10.1.5 caused a crash (bug 174663). The second installation attempt 
was successful.

However, after restart, attempts to display a composition window of any 
kind failed, hanging Mozilla. I was able to cure the problem by trashing 
the XUL Fastload File. CSS Editor is, indeed, visible in the Tools menu.