From the number of new downloads he has had to do, I think that a lot of online casinos do this, and I wonder how many players we affiliates lose everytime a player clears their cookie folder. Any player who is diligent about clearing cookies or running Ad-Aware or similar spyware cleaner is dropping the affiliate.
I have considered including some kind of statement on my webpages noting that clearing cookies my require a new download, and requesting a player bookmark my webpage the download came from in case a new download is necessary.
…Andrea
I often uninstall and reinstall or even redownload casinos. The thing to do is contact support and ask for your old account #. Few casinos will allow multiple accounts, so even if you’re able to do so, it’s not a good idea. 
For one thing, you’ll be denied any winnings, and have no recourse, since the Terms will clearly state that multiple accounts are not allowed. Casinos aren’t going to give welcome bonuses over and over until you win and cash out. That’s reasonable. So, if you inform your players to write down their account numbers, or contact support for their old accounts, then the question of cookies isn’t an issue.
Definitely give your players some guidance on this issue, since it is quite common.:blahblah: