VMS Help UIL, Compile Time Errors, ICON_WIDTH  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  ERROR:  The icons supported by  UIL  are  rectangular  (that  is,  x
  pixels  wide  by  y  pixels high).  As a result, each of the strings
  used to represent a row of pixels in an  icon  must  have  the  same
  length.   The  specified  row  does  not have the same length as the
  first row.

  USER ACTION:  Make all the strings in the  icon  function  the  same
  length.