XAMPP: XAMPP-Apache is already running.
XAMPP: Starting MySQL...
XAMPP: Couldn't start MySQL!
XAMPP: XAMPP-ProFTPD is already running.
XAMPP for Linux started.
肯定不是权限的问题，我试过了，
日志如下
120418 23:38:28 mysqld_safe Starting mysqld daemon with databases from /opt/lampp/var/mysql
120418 23:38:28 [Note] Plugin 'FEDERATED' is disabled.
120418 23:38:28 InnoDB: The InnoDB memory heap is disabled
120418 23:38:28 InnoDB: Mutexes and rw_locks use InnoDB's own implementation
120418 23:38:28 InnoDB: Compressed tables use zlib 1.2.3
120418 23:38:28 InnoDB: Initializing buffer pool, size = 16.0M
120418 23:38:28 InnoDB: Completed initialization of buffer pool
InnoDB: Error: auto-extending data file /opt/lampp/var/mysql/ibdata1 is of a different size
InnoDB: 0 pages (rounded down to MB) than specified in the .cnf file:
InnoDB: initial 640 pages, max 0 (relevant if non-zero) pages!
120418 23:38:28 InnoDB: Could not open or create data files.
120418 23:38:28 InnoDB: If you tried to add new data files, and it failed here,
120418 23:38:28 InnoDB: you should now edit innodb_data_file_path in my.cnf back
120418 23:38:28 InnoDB: to what it was, and remove the new ibdata files InnoDB created
120418 23:38:28 InnoDB: in this failed attempt. InnoDB only wrote those files full of
120418 23:38:28 InnoDB: zeros, but did not yet use them in any way. But be careful: do not
120418 23:38:28 InnoDB: remove old data files which contain your precious data!
120418 23:38:28 [ERROR] Plugin 'InnoDB' init function returned error.
120418 23:38:28 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
120418 23:38:28 [ERROR] Unknown/unsupported storage engine: InnoDB
120418 23:38:28 [ERROR] Aborting
120418 23:38:28 [Note] /opt/lampp/sbin/mysqld: Shutdown complete
120418 23:38:28 mysqld_safe mysqld from pid file /opt/lampp/var/mysql/jiankong01.pid ended
按照提示：xampp:
another
mysql
daemon
is
already
running.你的系统已经有一个mysql服务启动了，可能是你安梁灶培装xampp之前橡唯辩闹安装过其它版本的mysql，你可以将那个mysql服务停止再启动xampp或者将你xampp中mysql改一个端口也行。当然还有一种情况是你先前的关闭xampp服务时因意外，其中的mysql没有关掉，你把它关掉，再重启xampp就行了。
innodb插件在安装的时候就有异常，innodb引擎无法识别，建议你单独重装一个mysql
你重新安装XAMPP吧 文件缺损了