#3 _getXpathCount always return false

[ShockwaveNN]

Whenever i tried use _getXpathCount function - it's always return "false"
even in such form in simple html document
_getXpathCount(/html/body)

I tried use it in more complex exapmle - FireBug extension tell me, that thera several elements, by this XPath, but _getXpathCount always retrun 'false'

Test Enviroment:
Blueduck SDA 1.0.2
Selenium Server 2.0b3
Mozilla Firefox 3.6.16