Hi Jens,
I built the latest SD card image using the r336 package and it worked like a charm.
That "not found" package is not even included in the r336 anymore.
Btw, there is a brand new r339 in the testing folder and I just upgraded from r336 to r339 on my Raspi flawlessly.
Did you do a "sudo apt-get update"?
Are you using latest official raspbian image?
Cheers,
g.