entity 'symbol_name' does not have a value at the current PC (was
 optimized away)

    Facility: DEBUG, VMS Debugger

    Explanation: The value of the specified variable does not exist
    at this point in the program's execution. For example, the
    variable might be assigned to a register that is currently being
    used for some other purpose.

    User Action: Retry the operation at a point in the program's
    execution when the variable is being referenced.