VirtualWire or String causes arduino to hang

Using Arduino Programming Questions
4

PaulS:
How are you going to fit '1', '0', '2', '3' and the trailing NULL in a 4 element array?

Your array on the receiver is too small, too.

char Sensor1CharMsg[4];

Isn't the above a 5 element array (0 1 2 3 4), or have I got it wrong?

PaulS:
Anyway, I don't see you using the String class, so you have some other problem that fixing the String class/tool chain is not going to correct.

Ok thank you for helping me with that. Any thoughts on what might actually cause the hangs?