In 1.418 (2011/06/27) there was WipeOut permission introduced.
But when enabling it admins loose ability to do wipeouts.
I think, this happens because permission isn't linked with basic one.
I believe changing line in hudson.model.Item to something like that will fix the problem:

Permission WIPEOUT = new Permission(PERMISSIONS, "WipeOut", Messages._AbstractProject_WipeOutPermission_Description(), Permission.DELETE, Functions.isWipeOutPermissionEnabled(), new PermissionScope[]

);