Trigger Schedule script and getParameters

I've written a script that basically makes a report from a saved search, while changing one field on all the search results. I want to use a user event trigger to start the scheduled script, but trying to get the parameters is just giving me a null value. Here is the trigger code:

 var dashrec = scriptContext.newRecord;                  var acctperiod = dashrec.getValue('custrecordaccountingperiod');          var acctperiodname = dashrec.getText('custrecordaccountingperiod');          var rollBillCredits = dashrec.getValue('custrecord55');          if(rollBillCredits == true){          var scheduleRBC = task.create({              taskType: task.TaskType.SCHEDULED_SCRIPT              });          scheduleRBC.scriptId = 'customscript410';          scheduleRBC.deploymentId = 'customdeploy1';          scheduleRBC.params = {                  custrecordaccountingperiod: acctperiod  //                custrecordaccountingperiod: {  //                    value: acctperiod,  //                    name: acctperiodname  //                }          }          var taskId = scheduleRBC.submit();          }