Currently Being ModeratedMay 24, 2012 10:24 PM (in response to Linc Davis)
Succeded with booting into my Snow Leopard partion and backed up all data to my external.
Checked the logfiles after and "kernel: disk0s2: I/0 error" was on a few places, not as much as on Lion, but still it was there.
Gonna make a hardware-test this afternoon and check for errors.
If it shows nothing, then I guess I'll have to buy a new drive.