Error message proliferation

The example also points out another common occurrence.  GAMS usually generates multiple error messages as the consequence of a mistake.  Once an error is encountered numerous messages may appear as the compiler disqualifies all further usages of the item in question and/or becomes confused.  In the case above, subsequent references to the ELAPSED or PRODUCTS sets would cause errors and the SOLVE statement would be disqualified.  Thus, users should fix the errors starting from the beginning and skip later errors if in doubt of their validity.