Mozilla 1.2.1 won't open

I've been running Mozilla 1.2.1 on a Wallstreet PB under MacOS 9.2 &
had no trouble with the program until yesterday morning when it stopped
opening. 

The splash screen comes up with the line "starting up ...." & sometimes
I get the second line of "building first window " but then the splash
closes and the program is not running. 

I did download and briefly use the new iCab two days ago, but otherwise
have made no changes to my system in the last several weeks. Except for
some texts I was working on and e-mail & seemingly unrelated
preferences etc that change when programs are opened, most of of the
files created and/or modified in the days immediately preceding this
change in behavior are files in the iCab folder. 

Can anyone suggest what the problem might be?

Thanks, 

Herb