Lisp no longer working after company transferred networks

[eescobar55C7H]

I have tried unloading and reloading, moving the lisp files, and adding support files. I keep getting the same error:

Command: NSL
Please enter the layer name of the contours: nsl_tow
Select the Horizontal alignment:
Enter the vertical exaggeration <1>:
; error: bad argument type: numberp: nil

[paullimapa]

In order to load your lisp function I had to remove the semicolon you added in front of this line:

So now that line looks like this:

(alert
  "\n\nAuthor: M. Nadeem\n\nE-Mail:Nadeem_love@hotmail.com\n\nTHIS PROGRAM IS PROVIDED \"AS IS\" AND WITH ALL FAULTS.\n\nFOR ALL AUTO CAD VER.\n\nENJOY!
\n\nPress OK to continue."
)

Then in a blank drawing I added layer nsl_tow and drew a couple of plines then loaded your function:

I then ran your lisp and at the prompt to "Select the Horizontal alignment:" I chose the PLINE on the left.

The routine completed without an error:

So perhaps the problem has to do with your drawing?

I've attached my drawing NSL.dwg for you to try