Problem with GET_SEARCH_RESULTS - Parsing error

Hi experts,

I have a problem with using GET_SEARCH_RESULTS by RIDC. I want to use Native searchquery format, but I get csSearchQueryParserParsingError    

My code is:

   final DataBinder searchBinder = new DataBinder();
   searchBinder.putLocal("IdcService", "GET_SEARCH_RESULTS");
   String querytext;
   querytext = "dDocName = '" + dDocName + "'"; 

   searchBinder.putLocal("QueryText", querytext);
   searchBinder.putLocal("SearchEngineName", "database");
   searchBinder.putLocal("SearchQueryFormat", "Native");
   searchBinder.putLocal("ResultCount", "10");

   UcmUtils.executeService(searchBinder, "weblogic", true);

  I tried:

	"dDocName <matches> `" + dDocName + "`";
	MessageFormat.format("(dDocName = ''{0}'')", dDocName);
	"dDocName = '`" + dDocName + "'`";
	"dDocName = '" + dDocName + "'";
	"dDocName <matches> '" + dDocName + "'";
	"dDocName <matches> " + dDocName;

     "dDocName = `" + dDocName + "`"

Thank you

Martin