> I would like to copy some pdf files.  I realised
> that the files were being renamed during download so
> when for a usef defined structure with the following
> option:
> 
> %h%p/.%t

That structure does not make any sense.

Would help if you provided info as to where these PDF links live, but...
unfortunately due to the website you will be able to retain the filenames of
the PDFs (eg 00009zoc.pdf)

The default structure *should* work fine... I don't know why the numbering
would be reused.  The PDFs will probably be saved like:

pdf.pdf
pdf-2.pdf
pdf-3.pdf
etc