I got the error after an hardware failure on MySQL server while I tried to restart MySQL server innodb was not showing as a plugin , on checking the error log I got “InnoDB: Unable to lock ./ib_logfile0, error: 11 “ as I use NFS to store the mysql directory , from my previous expierence which is explained in http://onaxer.com/blog/blog/2010/06/01/innodb-unable-to-lock-ibdata1-error-37 ,
I tried doing these things
first - /etc/init.d/portmap restart
Second – /etc/init.d/nfslock restart
restarted the mysql and it worked like a charm.