>> It crashes with a message print out:
>>         Fatal error (11)Segmentation fault
>>
>> I'm running emacs-unicode-2 (CVS:2006-10-04) in Fedora core 5.
>>     
>
> Doesn't happen for me with CVS trunk on GNU/Linux (redhat 9.0).
>   

Strange, it does for me on GNU/Linux (Debian testing) as well as Windows..

Did you follow the exact formula Zhang Wei posted (across two different 
mails)?

    emacs -Q

    M-: (setq frame-title-format (list "%f (%l,%c) ---- @" system-name))

    C-h i m elisp <RET> m lists <RET> m rings <RET> u u


For me, the titlebar after the first u says (1, 2) with the cursor on line 21, column 2, where after the m lists it said (5091, 0) with the cursor on line 1, column 0 of the same manual page. Pressing C-l it says (21, 2), which is where the cursor is on the screen (as opposed to within the file, which I assume is where the 5091 came from), but pressing u again still causes a crash.