DB2-1053-00-E Invalid use of UNION keyword

The following conditions can cause this message:
Restriction: This topic applies only when the AppMaster Builder AddPack has been installed, and applies only to Windows platforms.
  1. ORDER keyword coded before the end of a UNION
  2. UNION coded in a DB-PROCESS structure
  3. More than one DB-DECLARE coded in a UNION

Check for the above conditions. See UNION syntax, examples and other coding guidelines.