functions borked after a certain time

[xavier <list.zsh-users@xxxxxxxxxxxxxxxx>]

Hello,

I use zsh 4.0.7 (i686-pc-linux-gnu)
with functions like this  :

if [ "$TERM" = "xterm" ]; then
setTitleAndIcon () {  print -nP '%{\e]2;'$1'\a\e]1;'$2'\a%}' }
preexec () { setTitleAndIcon $1 ${1%% *} }
precmd () { setTitleAndIcon %n@%m %m }
fi


after some time, the function is all borked :

$ functions setTitleAndIcon        
setTitleAndIcon () {
        itleAndIcon -nP dIcon
}


$ functions precmd
precmd () {
        % *} itleAndIcon %m
}


so each time i call anything, it tries to execute some non-sense code...
all my old shell in my old terms behave the same, they share 
the very same borked functions.

i did not upgrade zsh since thoses zsh started.

any clues ? 

thanks

-- 
xavier