Well, after some searching today (we applied the VMware Update 2 today, thus the VMware Tools update too), I finally found out what is causing that problem.
Though the problem seems to be not limited to virtual systems alone, I just browsed through this Novell Forum thread which pretty much describes my problem. I found the same error in the VM’s I tried to mount a CD image.
kernel: ide-cd: weird block size 524288
kernel: ide-cd: default to 2kb block size
Only difference between my behaviour and the one described, is that the virtual maschine is switched off immediately after you try to mount a CD image.
Now, this guy is saying Novell is working on it … But you’re gonna have to ask the question, why in gods name did such an update get through QA ? Or ain’t there no QA for updates ? *shrug*