bad sigarg pointer at pointer-addr or bad sigarg vector, can't read
 sigarg vector near sigarg-addr

    Facility: DEBUG, VMS Debugger

    Explanation: The debugger is attempting to chain down the call
    stack, following frame pointers, and has encountered an exception
    handler. The signal argument pointer at location pointer-addr
    points to a signal argument vector at least part of which is not
    read accessible near location sigarg-addr.

    User Action: Determine what part of your code is overwriting
    the stored signal argument pointer on the call stack, or part
    of the signal argument vector itself, and correct it. Since the
    debugger looks at the call stack to symbolize addresses, you may
    suppress some of these messages by typing the command "SET MODE
    NOSYMBOLIC".