web server returns "500 Internal Server Error" after sending this FormRequest using Scrapy

Question

I construct the following FormRequest according to httpFox(Firefox addon)'s content. However, web server alway returns "500 Internal Server Error".

Could someone help me on this?

The original url is: http://www.intel.com/jobs/jobsearch/index_ne.htm?Location=200000008

Here is my spider's skeleton:

class IntelSpider(BaseSpider):  
    name = "intel.com"  
    allowed_domains = ["taleo.net"]  

    def start_requests(self):  
        req_china = FormRequest("https://intel.taleo.net/careersection/10020/moresearch.ajax",  
                                formdata={
                                   'iframemode': '1',
                                   'ftlpageid': 'reqListAdvancedPage',
                                   'ftlinterfaceid': 'advancedSearchFooterInterface',
                                   'ftlcompid': 'SEARCH',
                                     ... # commentsThere are a lots of data here.#
                                   'location1L2': '-1',
                                   'dropListSize': '25',
                                   'dropSortBy': '10'},
                                callback=self.test)

        return [req_china]

def test(self, response):
    print response.body
    return