The exporter no longer works for jpeg files. After much trial and error, I tried this fix, which worked:
case "jpg":
app.jpegExportPreferences.jpegExportRange = ExportRangeOrAllPages.EXPORT_RANGE;
app.jpegExportPreferences.pageString = (pageIndex + 1).toString();
doc.exportFile(ExportFormat.JPG, filePath, false);
break;
The exporter no longer works for jpeg files. After much trial and error, I tried this fix, which worked: