Mysql start fails with Operating System error 13

I have XAMPP on my Ubuntu Lucid system and everything worked fine. But there seems to be some problem now and mysql wouldn't start.

I had tried to recover a few Drupal databases and hence copied the raw files to /opt/lampp/var/mysql folder like all other database folders. And, I guess that could have caused the problem. I am pasting the last few lines of the error log. Someone please help me out.

100814 15:08:29 mysqld_safe mysqld from pid file /opt/lampp/var/mysql/jitendra-laptop.pid ended
100814 15:17:47 mysqld_safe Starting mysqld daemon with databases from /opt/lampp/var/mysql
100814 15:17:47 [Note] Plugin 'FEDERATED' is disabled.
100814 15:17:47 [ERROR] Can't open shared library 'libpbxt.so' (errno: 0 API version for STORAGE ENGINE plugin is too different)
100814 15:17:47 [Warning] Couldn't load plugin named 'PBXT' with soname 'libpbxt.so'.
100814 15:17:48  InnoDB: Operating system error number 13 in a file operation.
InnoDB: The error means mysqld does not have the access rights to
InnoDB: the directory.
InnoDB: File name /opt/lampp/var/mysql/ibdata1
InnoDB: File operation cal开发者_如何学JAVAl: 'open'.
InnoDB: Cannot continue operation.

this worked for me:
sudo chown nobody.root -R /opt/lampp/var/mysql