If your in any hurry and it’s any help (DW’s advice is usually preferable), I just unzip the download file and upload all FILES from 1.gif down to upload.php but NOT the included folders (NOT attach, CGI or xtra) across into my ListMail folder on my server (I skip files that are not newer to save time). This has worked perfectly for me but I did only start with v1.8 when it was still in dev. I have uploaded like this about three times now and it seems to be the way to do it. It seems to agree with the instructions from DW on the updates page:
‘To upgrade, simply overwrite the main ListMail folder on your host with the new ones. You do not need to replace the CGI scripts or config.php. Once the files are uploaded, (re)login to ListMail for database changes to take effect.’
It doesn't overwrite config.php as the 'new' version is called config.php.txt.
DW thinks of everything.
This is just what I have done... if it helps any.