error fetching ABM page <num> in area <str>

  Explanation:  An error occurred during an attempt to  fetch  the
  given  ABM  page.   This could be because of a corruption in the
  RDB$SYSTEM area.

  User Action:  If there is a corruption that causes  this  error,
  correct  the  error with the RMU Restore command, and verify the
  database again.