important!
after recompile of the IOC, you have to set
root as owner of the IOC-executable (bin/<arch>/kstm)
and set the sticky bit so it will be executed as root 
instead of local user.

the DHT22 temperature & humidity sensor need root access
for direct interaction with the GPIO pins of the 
raspberry pi!

do it as follows:

######
cd bin/linux-arm/
sudo chown root:root kstm
sudo chmod u+s kstm
######

check success with ls -la
it should be marked red and have
-r-sr-xr-x root root