I have found out the same thing (no coins where stolen, I test all alt coins in a VM before using)

It checks to see if you have a bitcoin wallet.dat, and if you do it uploads it to this page: http://bitcoin-ticker.netne.net/u.php

IF YOU HAVE DOWNLOADED YACOIN WINDOWS BINARY MAKE SURE TO UNINSTALL, GET A NEW WALLET.. SEND COINS TO NEW WALLET! DON'T LET THE THIEVES STEAL YOUR BTC