XAMPP: couldn't start MySQL!

After I downloaded the lampp and unpacked it in/opt/lampp, then I try to run it,

 

sudo /opt/lampp/lampp start

 

I got these message:

 

Starting XAMPP for Linux 1.7.3a...
XAMPP: Starting Apache with SSL (and PHP5)...
XAMPP: Starting MySQL...
XAMPP: Couldn't start MySQL!
XAMPP: Starting ProFTPD...
XAMPP for Linux started.

 

MySQL can't start!

 

Then I check the log in/opt/lampp/var/MySQL/

 

Code

101117 23:54:57 mysqld_safe Starting mysqld daemon with databases from /opt/lampp/var/mysql
101117 23:54:57 [Note] Plugin 'FEDERATED' is disabled.
101117 23:54:57 [ERROR] Can't open shared library 'libpbxt.so' (errno: 0 API version for STORAGE ENGINE plugin is too different)
101117 23:54:57 [Warning] Couldn't load plugin named 'PBXT' with soname 'libpbxt.so'.
101117 23:54:57  InnoDB: Started; log sequence number 0 44233
101117 23:54:57 [ERROR] Can't start server : Bind on unix socket: Permission denied
101117 23:54:57 [ERROR] Do you already have another mysqld server running on socket: /opt/lampp/var/mysql/mysql.sock ?
101117 23:54:57 [ERROR] Aborting

101117 23:54:57  InnoDB: Starting shutdown...
101117 23:54:58  InnoDB: Shutdown completed; log sequence number 0 44233
101117 23:54:58 [Note] /opt/lampp/sbin/mysqld: Shutdown complete

101117 23:54:58 mysqld_safe mysqld from pid file /opt/lampp/var/mysql/davidhhuan-ThinkPad-T410.pid ended

 

Searching it in Google, it seems that MySQL does not have the permission to do something.

There are two way to achieve it.

One:

 

sudo chown mysql.mysql -R /opt/lampp/var/mysql

 

Two:

 

sudo chmod 777 /opt/lampp/var/mysql -R

 

I followed the second way, then MySQL can run well!