I'm trying to use the provided examples but i can't get them to work. There is no error, but the swf button is not being loaded, why?

Here is my code:

var swfu;

window.onload = function () {
swfu = new SWFUpload({
// Backend settings
upload_url: \"".JURI::base()."components/com_newster/upload.php\",
file_post_name: \"resume_file\",

// Flash file settings
file_size_limit : \"10 MB\",
file_types : \"*.jpg;*png;*.gif\",
file_types_description : \"All Files\",
file_upload_limit : \"4\",
file_queue_limit : \"0\",

// Event handler settings
swfupload_loaded_handler : swfUploadLoaded,

file_dialog_start_handler: fileDialogStart,
file_queued_handler : fileQueued,
file_queue_error_handler : fileQueueError,
file_dialog_complete_handler : fileDialogComplete,

//upload_start_handler : uploadStart,
upload_progress_handler : uploadProgress,
upload_error_handler : uploadError,
upload_success_handler : uploadSuccess,
upload_complete_handler : uploadComplete,

// Button Settings
button_image_url : \"".JURI::base()."components/com_newster/uploader/button.png\",
button_placeholder_id : \"spanButtonPlaceholder\",
button_width: 61,
button_height: 22,

// Flash Settings
flash_url : \"".JURI::base()."components/com_newster/uploader/swfupload.swf\",

custom_settings : {
progress_target : \"fsUploadProgress\",
upload_successful : false
},

// Debug settings
debug: true
});
};

also i've:

where can i start to look? I'm using firebug and there is no errors, and js scripts are being loaded...:S

regards