This is indeed not how the update process should work.
While I investigate how to fix this you can try to use the following update url:
http://www.whatever.com/logaholic/update.php?conf=Profilename&lgpkey=[md5 of username]:[md5 of password]&reset=1
Please note you have to fill in the bold parts with your own data.
So, your cronjob command (for linux) will look something like this:
wget -q -O /dev/null http://www.example.com/logaholic/update.php?conf=profilename&lpgkey=d41d8cd98f00b204e9800998ecf8427e:d41d8cd98f00b204e9800998ecf8427e&reset=1
Should you need any more help visit the cronjob page on http://www.logaholic.com/manual/LogaholicManual/AutomatingUpdates.