Hi,
when I select to "Boot Linux from Partition 2" in rEFIt, it tries to boot from CD. If there isn't a CD in the iMac, It shows "Fehler beim Laden des Betriebssystems"
what means Error by loading the Operating System.
On partition /dev/sda2 (The Linux partition) is LILO in the PBR installed.
What can I do?
I think the "Boot From CD" problem is a problem with the Mac's emulated BIOS and not with rEFIt. You can test this by using the Startup Manager instead of rEFIt (hold the Option key at startup and then select Windows).
Check the contents of the MBR using fdisk. Compare it to the GPT using gpt. Use http://members.shaw.ca/joevt/dumpvols2.sh.zip in Terminal.app to describe your partitions and post the results here.
You might need to boot the Linux CD to repair your Linux partition.