require: Symbol's function definition is void: eieio-defmethod

Trying to run `M-x semantic-mode` gives me the following error:

  require: Symbol's function definition is void: eieio-defmethod

I'm currently on:

  GNU Emacs 23.4.1 (x86_64-unknown-linux-gnu, GTK+ Version 2.24.10)

CEDET Version:	1.0
  			Requested	File		Loaded
  Package		Version		Version		Version
  ----------------------------------------------------------
  cedet:		1.0		nil		ok
  eieio:		1.3		ok		ok
  semantic:		2.0		nil		ok

I cannot find any mentioning of eieio-defmethod anywhere in my site
files and trying to build cedet from sources fails with the same error
messages.

Any idea what causes this and how to fix it?

Cheers,
Philipp Moeller

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