It's not possible to spoil or let the drive spark just by cutting the traces. The drive is only damaged when you rejoin it with silver glue and short it out.
The drive sparks since rejoining the traces improperly will cause a short in the traces by combining with the rest of the others. Therefore a lot of power will get inside the pads and burn it.
So did you get the key? Did it spark after rejoining traces or before rejoining traces?
EDIT: All you have to do is buy a new LiteON drive here -
http://www.tiaowiki.com/forums/xbox-360-hardware-talk/how-to-spoof-and-flash-to-a-new-liteonbenq/ |
http://www.consolesource.com/ecomm/catalog/Parts--Repair-orderby0-p-1-c-272.html