onFileUploadError

fires in case of a server-side error during uploading

void onFileUploadError(object file,object response);

file	object	the file data
response	object	a server-side response (if any)

$$("uploader1").attachEvent("onFileUploadError", function(file, response){
    //code
});

Details

The events fires only when the server-side response contains the error status, like:

echo "{ status:'error' }";