something i noticed is that when xLib isn't installed, it gives ERR:ARGUMENT (the real(3,5) call after storing Pic5 the first (i think) time.
I suggest adding a check for xLib at the beginning of the program:
real(11
83+Ans/2->A
A will equal 88.5 if no xLib, or 83, 83.5, 84, or 84.5 with xLib corresponding to the calculator model!
EDIT: When Omnicalc is installed instead of xLib, it gives the error after a screwed-up title screen and picking items from the menu.