Barcode scanner using USB shield on Arduino Mega

Hi,

I am working on a project, wherein I intend to create a standalone device that operates away from the computer.
I have to use a barcode scanner for my project. The model I am using now is the CCD USB barcode scanner, FG8100.

I have found a few very useful tutorials online that provide guidance on how to use the barcode scanner with a USB shield with Arduino. One such example is from the following website :

For some reason however, the code simply does not work for me.

When I compile the code,I do not get any errors. However, once I run the code, I am told that the "OSC does not start". This , I understand is because the USB Init () function fails. I am not quite sure what this means though.
The only difference I find from the example is the choice of USB shield used. The barcode scanner, although of a different model, mirrors the protocol and class settings as that used in example, so i doubt this is an issue as well.

I am currently using a sparkfun USB shield(MAX3421E), with an Arduino Mega 2560.
Any help would greatly appreciated.