title: Lisp - bad argument type: numberp: nil
body: <p>I am writing a function that removes background mask from all mtext, however, I am getting a <code>bad argument type: numberp: nil</code> error after running the code:</p>
  
  <pre><code>(defun c:bgm ()
      (vl-load-com)
      (setq ss1 (ssget "X" '((0 . "MTEXT")(-4 . "&lt;OR")(90 . 1)(90 . 3)(-4 . "OR&gt;")))); selects all mtext with background mask on
      (setq sscount (sslength ss1))
      (repeat sscount
          (setq mtxtobj (entget (vlax-vla-object-&gt;ename (ssname ss1 counter))))
          (vla-put-backgroundfill mtxtobj :vlax-false)
          (entmod mtxtobj)
      )
  )
  </code></pre>
  
  <p>Any ideas why?</p>