it will be hard without the whole variable definition but...
Code:
BUTTON INITIATE_COMM, 1, 255, 0, C7, 0, RX -line 258, ID not Label
how you defined C7 and RX?

Code:
BUTTON INITIATE_COMM, 1, 255, 0, C7, 1, RETURN -line 265, bad exp
RETURN is a reserved word.. you MUST use a label name where to jump. On this label you will use a return.

Code:
SERIN2 SERIAL_INPUT, 600, [WAIT("A"), BIN MODE] - line 272, bad exp
Shouldn't be a problem... and you know that 600 is not 600 bauds right?