Feeds Image Grabber not running fine in Nginx?

I've installed Feeds Image Grabber in ubuntu desktop. Everything running fine.
And then Im trying in Centos server running nginx.

Firstly, I test Feeds without Feeds Image Grabber. Everything running fine.

And then I activated Feeds Image Grabber. I not check "Import on submission", and I submit some RSS feed URLs. After some cron run, no new feed items aggregated. When I run cron manually, the cron finished in very short time, just like no task for the cron... and still no new feed items aggregated.

I tried checking "Import on submission", and then submit feed URL. When clicking "save", a message appeared:

An error has occurred.
Please continue to the error page
An HTTP error 500 occurred. /batch?id=15&op=do

The RSS feed URL submitted as Feeds feed node, but no feed item created. When I submit once again (same RSS feed URL or new one), that error message appeared again, but the /batch?id=15 become /batch?id=16. that number will always increased by 1 when I submit once again.

On the current Feeds feed node, when clicking "import", that error message appeared again... and also with increased batch id

This is not resource issue (memory/timeout).. my desktop even lower than that

I dont remember the first batch id number... I think it was 1

server spec and installation:

    * nginx 0.6.39
    * Feeds Image Grabber version= 6.x-1.0
    * feed url and FIG settings
    * CCK 6.x-2.9, filefield 6.x-3.9, imagefield 6.x-3.9
    * OS=Centos 5.4 x86
    * mysql version=5.0.77
    * php version=5.2.14