Thanks for the answers.

Should I do step three in the deinstallation guide also?
Or does the following fix it?

sudo gainroot
apt-get install --reinstall -y kernel kernel-flasher

apt-get remove kernel-power kernel-power-modules

When i type step 3:

flasher-3.5 -f --flash-only=kernel -R -F RX-51_2009SE_3.2010.02-8_PR_COMBINED_MR0_ARM.bin

It says

/bin/sh: flasher-3.5: not found