Firefox requesting unexpected page

I'm working with Firefox 2.0.0.12, which I've modified to run over SCTP 
rather than TCP.  I occasionally run into a problem where, on startup, 
Firefox tries to send a "GET /project/%APP%/%VERSION%/whatsnew/" to 
www.mozilla.org, rather than going directly to my home page.  Since 
www.mozilla.org isn't running over SCTP, there's no response, and 
Firefox just keeps sending INITs (like a SYN for TCP) and never gets 
beyond this stage.  I've tried to disable everything I can think of that 
might be causing this (updates, feeds, favicons, ...), but without 
success so far.  Any suggestions on what else I might try would be very 
welcome.