There are different subclipse versions for different Eclipse and subversion versions.
Eclipse 3.4 (NatONE 81) and Eclipse 3.6 (NatONE 8.2).
Subversion 1.5.x requires subclipse 1.4.x
Subversion 1.6.x requires subclipse 1.6.x
A good combination is for example: NaturalONE 8.2 + subclipse 1.6.5 + subversion 1.6.1.