omeka not harvesting in windows

i have omeka 2.3.1 by wamp on windows 8.
i run two instance of omeka but when harvest content of each other nothing happen! the status was fixed to Queued.

i tested harvesting between one of the windows instance and linux omeka instance that items were harvested successfully.

why this happened?
what am i do to solve this issue on windows?

need to mentioned: i set php cli path on the location of php.exe in wamp.
another omeka instance are installed on the virtual ubuntu machine.

Are you using OAI-PMH Harvester or the API import?

Hi mebrett!
thanks for answer.

i using OAI-PMH Harvester.