What does 'input in flex scanner failed' really mean?

[Bob Rogers]

   I am stumped by the following problem:

        [EMAIL PROTECTED]> cat scanner.pir
        ## WTF???
        .sub main :main
                load_bytecode "Data/Dumper"
        .end
        [EMAIL PROTECTED]> ./parrot scanner.pir 
        input in flex scanner failed
        [EMAIL PROTECTED]> 

This is with vanilla r14850.  I can't seem to get it to accept
load_bytecode under any circumstances.  Does anyone have any clues?
MTIA,

                                        -- Bob Rogers
                                           http://rgrjr.dyndns.org/