Try the following:
//find librxtxSerial library that works for this system
find /usr -ls 2>&1 | grep -i librxtxSerial
// make a backup of librxtSerial
mv /home/XX/ohjelmointi/bin/arduino-0022/lib/librxtxSerial.so /home/XX/ohjelmointi/bin/arduino-0022/lib/librxtxSerial.so.orig
// create a link to (replace XXX with the path from the find command)
ln -sf /XXX/librxtxSerial.so /home/XX/ohjelmointi/bin/arduino-0022/lib/librxtxSerial.so
run arduino
let us know what happen?