CSV Import - Unexpected Error

Hi,

This is my first try at running a CSV Import from a file attached to a case. I'm having no trouble pulling the file with a saved search, but I keep getting:

"UNEXPECTED ERROR during CSV Import process" on nlapiSubmitCSVImport()

Here is what I'm working with:

function importCsvFile(){      var messageSearch = nlapiSearchRecord("message",null,          //start by setting up criteria      [         ["subject","contains","ITEMIMPORT"],          "AND",          ["messagedate","within","today"]       ],           //and then the results page      [         new nlobjSearchColumn("internalid","attachments",null)       ]      );      for (var i=0;i<=messageSearch.length-1; i++){           nlapiLogExecution('debug','test',i);          var fileId = messageSearch[i].getValue('internalid','attachments',null);          nlapiLogExecution('debug','fileId = ',fileId);          var import = nlapiCreateCSVImport();           import.setPrimaryFile(nlapiLoadFile(fileId));          import.setMapping('CUSTIMPORTImportItemMapping');           import.setOption('jobName','itemImport');          var importId = nlapiSubmitCSVImport(import);           nlapiLogExecution('debug','importId = ',importId);      }  }