Well. I've been playing around with this bit of code to correct the issue with arced segments. It ALMOST works. That is - it finds the correct intersect point on a polyline with straight and arc segments (evidenced by the line drawn). However - for some reason the curve distance is not always returned, but works only intermittently. I cannot figure out why yet.
I know there are probably more complicated and reliable ways to do this, but I was attempting to keep it simple. I'm sorry but I don't have the knowledge to write anything more complex in a reasonable time. 
Perhaps one of the other Guru's here could write something faster than I could, or figure out why my above code is not getting the curve distance reliably.
No worry and don't be sorry, buddy. Your help is very much appreciated.
I know AutoCAD behaves differently under this circumstances. Try to move any object on the testing drawing to 0,0, they won't move. Also you can try to copy, it won't work either. I tried several visual Lisp routine from John Burke and Lee Mac (*Polyline routine), their codes don't always work either. In this situation, where the real world coordinates are so big, I was forced to re-wrote my codes back to the 'standard lisp', involved some geometry, but I found out it's more robust and dependable. Once again, thanks for all your help.
