Library /sys$common/syshlp/basichelp.hlb Compile time errors, JMPBADBLO  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  ERROR - The program attempts to transfer control to a  WHEN  block  or
  associated  handler.   Change  the  program  logic so that it does not
  transfer control to a WHEN block or associated handler.