Hello,
(i could log in to g potato so it shouldn't be wrong).
To log in the game you need to enter you email and pwd from your brand new my.com account.
Old gpotato id doesn't work with the new launcher :
http://en.allods.com/mycomgames
So if you have made the transfer with a certain email and password, try again to log in the game with it.
I'm not sure what happened with the my.com accounts you made after that ?
Incase, read the news from Allods site, there is a lot of informations about lost characters since transfer.
http://en.allods.com/news
(transfer issues and updates)