Error ???

I have a program that draws geometry.
It worked under any circumstance in R14.
It has an undo "BE" and undo "End" so when I undo, it completely undos several loops of drawing.
In R2005 I can run it, but if I undo it then try to run it again I get an error:
Command: area_clear3
Select internal point: < point >
Calculating offsets......Please wait.
Error: AutoCAD.Application: Object was erased

All my variables are local so it shouldn't be looking for an object that was erased.
I can erase the geometry and then run the program again and it workes fine.
If I re-open the drawing it works okay.
Any ideas?
TIA
Bill

 

Sorry for any inconvenience.
I found a floating variable and learned a new lesson.

If a variable is set to a vlax-object and the object is erased, the variable will still read:
Command: !@cv_ray
#<VLA-OBJECT IAcadRay 0e6e8f14>
But when attempting to turn that into an ename:
Command: (vlax-vla-object->ename @cv_ray)
nil
BTW: John U., the new @cv_inside with "look ma no rays" did not work so good with my program while the older version with the ray works great.

I'm going to have to quit asking you guys about this stuff 'cause I end up figuring it out for my self anyway. ;-)

Thanks

Bill