BL4S100 Xbee Problem

I try to change the mode from ROUTER to COORD using the program modemFWload. After it is done, I always find an error message " xbee_init failed. result code: -5 (I/O error) " while trying to run other programs.

I notice the DS1 LED from the Assoc pin is off. Its on before I run program modemFWload.

I am using DC10.64.

Anything I’ve done wrong?