Autoit + Xpath: Error using ff.au3 -

i tried use _ffxpath in combination _ffclick (both part of ff.au3), doesn't click object:

my relevant code line:

$obj = _ffxpath("//div[contains(@class,'jobgroup-9')]", "", 9) _ffclick($obj) 

i know xpath correct, because:

$pos = _ffgetposition(_ffxpath("//div[contains(@class,'jobgroup-9')]", "", 9)) 

returns correct position (i know can combine controlclick, don't want "dirty")

thanks in advance, derrod