avr plugin Fehler bei Installation

Eclipse (Helios) teilt beim Installieren mit:

"Cannot complete the install because one or more required items could 
not be found.
  Software being installed: AVR Eclipse Plugin 2.3.3.20100701PRD 
(de.innot.avreclipse.feature.group 2.3.3.20100701PRD)
  Missing requirement: AVR Eclipse Plugin 2.3.3.20100701PRD 
(de.innot.avreclipse.feature.group 2.3.3.20100701PRD) requires 
'de.innot.avreclipse [2.3.3.20100701PRD]' but it could not be found"

Was will mir das sagen, und was muss getan werden?

Gruss

Robert