The cool thing is the answer is in the error message.
Error[101] DT_INTS-14 TEST.ASM 235 : ERROR: (wsave variable not found,)
Error[101] DT_INTS-14 TEST.ASM 201 : ERROR: (" Add:" wsave VAR BYTE $20 SYSTEM)
So..
Put
wsave VAR BYTE $20 SYSTEM
in your code's variable section.