Library /sys$common/syshlp/dbg$help.hlb DEBUG, Messages, VFLTUND  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 Reserved operand, encoded as floating underflow

    Facility: DEBUG, VMS Debugger

    Explanation: An arithmetic exception condition occurred as a
    result of floating-point underflow.

    User Action: Examine the code that caused the fault. Verify that
    the operands or variables are specified correctly. Verify that
    the encoded reserved operand was not deposited by a non-floating-
    point operation.