■ An invalid expression has been used to assign a value to a
  symbolic constant.
 
■ Possible solutions:
 
  • Make sure that your numeric expressions assigned to
    symbolic constants contain only:
    ♦ Numeric literals
    ♦ Previously defined symbolic constants
    ♦ Arithmetic or logical operators (all except
      exponentiation)
 
  • Make sure that your string expressions assigned to
    symbolic constants contain only a single literal string,
    enclosed in double quotation marks.
 
■ If you need additional help, move the cursor to a keyword
  and press F1 to open the Help window.