The XBee module sends the Modem Status frame to the host, and it's not the result of the module receiving a packet. Try dumping the rest of the Modem Status frame to see what status the XBee module is trying to report. It might be reporting Hardware Reset (0x00), followed by Coordinator Started (0x06).
The XBee Series 1 documentation includes a list of all possible Modem Status values.
BTW, updating the sprintf(tmp, "%d", c);
to use "0x%02X"
as the format string will print the frame type in hex and make it easier to look up frame types in the documentation.