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

 maximum file name length is 251 characters

    Facility: DEBUG, VMS Debugger

    Explanation: The name of the file specified by the user is too
    large for the debugger to handle

    User Action: Try to redo the operation with a shorter string.