Looks like a bug in the macro. Report it to GS per mail please. You can fix it by your own to avoid error message, You have to modify the certain line (1003 ) in the script. Jump to it by Command-L in the macros 3D-script.
There has to be something like
PEN WALLSKINSPARAMS[...][7 or 9]
in this line. The pen number aftre PEN may not be less than 1. You can proof this by
IF WALLSKINSPARAMS[...][7 or 9]>0 THEN PEN WALLSKINSPARAMS[...][7 or 9]
[...][7 or 9] you have to change as it is written in the line.
Make shure to have a backup of the GSM before you do any changes.
😉