Can't connect to local MySQL server (no replies)

Hello everyone, first of all sorry for the bad English but I am Italian. in practice, I messed up on my Macbook Pro running OSx lion to change the password for mysql.
now if I run from terminal:

/ usr / local / mysql / bin / mysql-st

the system answers:

ERROR 2002 (HY000): Can not connect to local MySQL server through socket '/ tmp / mysql.sock' (2)

I tried to reinstall mysql-5.5.17-OSX10.5-x86_64.dmg, then the MySQLStartupItem and finally MySQL.prefPane (which does not work with my mac because is incopatibile with Intel processor ...????) but the situation is the same...


ERROR 2002 (HY000): Can not connect to local MySQL server through socket '/ tmp / mysql.sock' (2)

please help me to resolve my problem,

thanks in advance