Log Errors

Can someone please explain the use of scrapeableFile.addHTTPParameter? I think it is what I need to solve my problem but the log tells me this:

Data Records: An error occurred while processing the script: Set _dlc

Data Records: The error message was: Attempt to invoke method: addHTTPParameter() on undefined variable or class name: SiteResults : at Line: 3.

This is my script:
SiteResults.addHTTPParameter( new com.screenscraper.common.HTTPParameter(
"_dlc", "RESULT_COUNT", 1, com.screenscraper.common.HTTPParameter.TYPE_GET ));

This code is in a script file called Set_dlc and I am calling it in the scripts tab of the SiteResults scrapeable set to run 'Before File is Scraped'

The session seems to run as I do see the data in the log, but the error message leads me to believe that I may not have something set up quite right.

Thanks in advance.