What am I doing wrong with this foreach?

When I step through this part of my code I'm getting a "bad argument type: stringp nil" error at the "(substr pcbn 1" line, which is wierd, because when I add a watch to that expression everything looks legit. Anyway here's my code:

;;;  (setq ucbl     ;\
;;;  (vl-directory-files pcbl "*.dwg")  ;>This is the actual code of my program, but you don't have the file paths I use.
;;; )     ;/
 (setq ucbl '("1 - No Valet Note.dwg" "2 - Lines Test.dwg")) ;This is what ucbl is set to when I run the above code.
 (setq cbnl "New ?")
 (foreach pcbn ucbl
   (setq cbnl
   (strcat
     cbln
     " "
     (substr pcbn 1
      (vl-string-search " - " pcbn)
      )
     )
  )
   )

Any and all help would be greatly appriciated.

Nevermind... this post can be deleted... I switched two letters in one of my variables.