Error with file descriptor

[Aljosha Papsch]

Does anyone have a solution for that problem:

ModManager() {
 ClearFiles -4
 echo "zenity --list --window-icon=\"${run_path}icon.png\" 
--width=\"650\" --height=\"350\" --title=\"${modmanager[${lang}]}\" 
--text=\"${RegMods[${lang}]}:\" --column=\"${no[${lang}]}\" 
--column=\"${name_loc[${lang}]}\" --column=\"Modus\" \\" >&4
 for (( a = 1; a <= MODULES; a++ ))
 do
   echo "${a} \"${mod[${a}]} in ${loc[${a}]}\" ${mode[${a}]} \\" >&4
 done
 echo "__ ___________________ __ \\" >&4
 echo "add \"${add_mod[${lang}]}\" __ \\" >&4
 echo "del \"${del_mod[${lang}]}\" __ \\" >&4
 echo "back \"${back[${lang}]}\" __" >&4
 command=`. ${tmpmenu}`
 case ${command} in
   "add") AddModule ;;
   "del") DelModule ;;
   *) Main ;;
 esac
}

This function allows the user to manage the modules that are registered 
in the scripts configuration files.
First it "build" a zenity command. This is necessary because of the for 
statement. That provide the information about the modules. All lines are 
send to the file descriptor 4. Before, to do not annoy the script, the 
file behind descriptor 4 is cleared with the function ClearFiles. 
Finally the command is executed and the result is compared.
If I want to use the ModManager function, all I get is nothing. It just 
do a break.

Here you have the function ClearFiles:
ClearFiles() {
   while [ -n "$1" ]
   do
   case "$1" in
   -3) cat /dev/null > ${tmptmp} ;;
   -4) cat /dev/null > ${tmpmenu} ;;
   -5) cat /dev/null > ${tmp_getcmd} ;;
   -6) cat /dev/null > ${tmp_goon} ;;
   esac
   shift
   done
}