MCP2515, CAN bus, and transmission failure
IF you look at the power supply your MCP2551 transceiver has a higher minimum input voltage than your MCP2515 this caused some issues in my last project as there was quite a big voltage drop once everything was connected the controller MCP2515 was working but the transceiver was under powered 

Also I would recommend using only the Transceiver with the propeller here is a nice library for you to try: 

http://obex.parallax.com/object/745

I got this working in a few seconds using a propeller and MCP2551 on a breadbord