If you start with the assembly language template generated by CCS, then the template will include the following lines:
;——————————————————————————-
.cdecls C,LIST,”msp430.h”
;——————————————————————————-
.def RESET
;——————————————————————————-
However, the code on Page06, Lesson06,  is missing the “.def RESET” line. So if you copy the code from Page06 verbatim then this line will be missing, which will give rise to errors. Please make sure that you have the line “.def RESET” line in your code.