Hyperstring on Delphi 6: Operand size mismatch

I got the following error when I tryed to compile the hyperstring library on
Delphi 6:

[Error] HYPERSTR.PAS(846): Operand size mismatch

the lines are (assembler):

    Bts   EBX,DL

or

    Bt    EBP,DL

Can anyone say me what's wrong?
Thank You.