Firefox make some sound like bell

I have update firefox to 2.0.0.7 about 3 hour ago, but I hair some
sound like bell when firefox start and runing.

why?

and I have got some message like this when execute firefox -h

Type Manifest File: /usr/local/lib/firefox/components/xpti.dat
###!!! ASSERTION: Failed to write xpti manifest!: 'Error', file
xptiInterfaceInfoManager.cpp, line 1937
Break: at file xptiInterfaceInfoManager.cpp, line 1937
*** Registering Apprunner components (all right -- a generic module!)
nsNativeComponentLoader: autoregistering begins.
nsNativeComponentLoader: autoregistering succeeded
###!!! ASSERTION: Failed to write xpti manifest!: 'Error', file
xptiInterfaceInfoManager.cpp, line 1937
Break: at file xptiInterfaceInfoManager.cpp, line 1937
nsNativeComponentLoader: registering deferred (0)
  -jsconsole           Open the Error console.
  -browser            Open a browser window.
  -inspector <url>     Open the DOM inspector.
Usage: firefox [-flags] [<url>]
WARNING: nsExceptionService ignoring thread destruction after
shutdown, file nsExceptionService.cpp, line 191
WARNING: No event queue listener?, file nsEventQueue.cpp, line 79
Could not write out perisistant registry!
nsStringStats
 => mAllocCount:           5064
 => mReallocCount:          943
 => mFreeCount:            5064
 => mShareCount:           5426
 => mAdoptCount:            191
 => mAdoptFreeCount:        190  --  LEAKED 1 !!!

my system informations:

FreeBSD local.khsing.net 7.0-CURRENT FreeBSD 7.0-CURRENT #7: Thu Sep
13 12:47:13 UTC 2007
root_at_local.khsing.net:/usr/obj/usr/src/sys/D600  i386


-- 
_______________________________________
Mr. Gawain Bai, PinYin: Guixing Bai, Wade-Giles: Kueihsing Pai
Email: wike1985_AT_gmail_DOT_com
blog: http://cnwike.blogspot.com  this for work
        http://blog.donews.com/kueihsing this for study.
give me free or give me death.