ener.hlp (Topic list)
Important Notice
The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.
Expression too complex
■ Certain internal limitations of Visual Basic have been
  exceeded.
 
■ For example, during expression evaluation, strings that are
  not associated with variables are assigned temporary
  locations. A large number of such strings or a numeric
  expression with many complicated subexpressions can cause
  this error.
 
■ Possible solution:
 
  • Simplify expressions or assign strings to variables.
 
■ If you need additional help, move the cursor to a keyword
  and press F1 to open the Help window.