Need Help! Alarm 531: Macro nesting too deep.

Hi guys,

I've been at the machine all day trying to accept my macro program, and I keep getting the 531 alarm code "Macro nesting too deep." I'm only calling one program, macros are enabled, and my variables are set. No idea what's going wrong. Any help would be appreciated.

Thanks

P.S. I know the program looks weird. It's for university research to try and oscillate the z-axis with a macro.

***Main Program to call Macro program***
%
O10085
G18;
G54 T0101;
G65 P9018 L1;
M30;
%
*****

Variables in Macro Program
#100=0.000
#101=-1.000
#102=0.0138
#103=0.0017
#104=0.0016
#105=0.0162
#106=6.269
#107=1.7584
#108=1.6682
#109=4.894

***Macro Program**
%
O09018
G91
WHILE [ #100 GT #101 ] DO1
G01 Z [ #100 - #102 ] F#106
#100= #100 - #102
G01 Z [ #100 - #103 ] F#107
#100= #100 - #103
G01 Z [ #100 + #103 ] F#108
#100= #100 + #103
G01 Z [ #100 + #104 ] F#109
#100= #100 + #104
G01 Z [ #100 + #105 ] F#108
#100= #100 + #105
G01 Z [ #100 - #105 ] F#107
#100= #100 - #105
END1
M99
%
****