Not sure if it is the same on the 5600, but on the Cxx0 the script /etc/rc.d/rc.rofilesys or /root/etc/rc.d/rc.rofilesys (there are 2 for some reason and they are sometimes different on differnt roms) has a line at the bottom the reads
echo $LAUNCH > /home/sharp/etc/launch.default
where by default $LAUNCH is \"q\" also /etc/inittab has the following
ln:345:respawn:survive -l 6 /sbin/launch
meaning that for run levels 3,4 and 5 (the default) it runs /sbin/launch, whick looks in /home/sharp/etc/launch.default for a single letter to choose what to run. By default it runs /home/QtPalmtop/qpe.sh.
When you disable qpe.sh, it respawns and launch tries to run qpe.sh again, fails, respawns etc etc etc.
So you need to
a) edit rc.rofilesys to pass \"a\" instad of \"q\" or
edit /etc/inittab to run something else for runlevel 5 or
c) edit /etc/inittab to run something else for a new default runlevel
Hope that helps
Stu