Phpmyadmin error #1045

[python256]

Hello

I'm using XAMPP 1.8.3-4, and I use apache / easyphp for years now, but I remain stuck with a stupid permission error while trying to access phpmyadmin :
#1045 MySQL server connexion not allowed.

I'm really disappointed with the quality of the app : Permanent problems with permissions, bugs...
Seriously it would have been tested more in-depth, because users don't have to pass entire days trying to understand particular exception or logic...
I know that these words will not solve my problem, but dev has just to understand that things must be seriously tested and remains efficient for the final users.

Now I have a big database stuck into my own computer;
I tried to edit phpmyadmin config.inc.php : no change
I tried to edit mySQL conf file my.cnf : no change !

So please, help me because I'm completely stuck now.
Thanks for any help you could provide