starting mysqld is giving error as:
Timeout error occurred trying to start MySQL Daemon.

/var/log/mysqld.log says:

###############
090909 13:17:27 mysqld started
090909 13:17:27 InnoDB: Database was not shut down normally!
InnoDB: Starting crash recovery.
InnoDB: Reading tablespace information from the .ibd files...
InnoDB: Restoring possible half-written data pages from the doublewrite
InnoDB: buffer...
090909 13:17:27 InnoDB: Starting log scan based on checkpoint at
InnoDB: log sequence number 0 29007405.
InnoDB: Doing recovery: scanned up to log sequence number 0 29007405
InnoDB: Last MySQL binlog file position 0 1056, file name ./mysql-bin.000002
090909 13:17:27 InnoDB: Started; log sequence number 0 29007405
090909 13:17:27 [ERROR] Fatal error: Can't open and lock privilege tables: Unknown collation '#46' in table 'host.frm' definition
090909 13:17:27 mysqld ended
#######################

I have been hunting the issue since long but I am not able to figure out what is wrong with the installation/ its configuration.
Thanks in advance for any insight..

Are you running this as root? And how are you trying to start mysql? What version/distro of Linux and MySQL are you using??

Since there's an abnormal shutdown warning, that says that the database wasn't shut down correctly, usually indicative of the system script not being called, and the process being killed instead. As root, type in "/etc/init.d/mysql start" and see what happens.

Hi TB0ne
Thanks for looking into
I am trying "service mysqld start" and "/etc/init.d/mysqld start" as root itself.
Here is the information regarding the system

[root@oelserver ~]# uname -a
Linux oelserver.home.com 2.6.18-128.el5 #1 SMP Wed Jan 21 08:45:05 EST 2009 x86_64 x86_64 x86_64 GNU/Linux
[root@oelserver ~]# cat /etc/issue
Enterprise Linux Enterprise Linux Server release 5.3 (Carthage)
Kernel \r on an \m
[root@oelserver ~]# cat /etc/redhat-release
Red Hat Enterprise Linux Server release 5.3 (Tikanga)


Instead when trying "/usr/libexec/mysqld --skip-grant &", daemon starts while only giveing warning
"Can't open and lock time zone table: Unknown collation '#45' in table 'time_zone_leap_second.frm' definition trying to live without them".

But problem with this is that I need MySQL server for bugzilla and am not able to grant privileges to the bugzilla user

MySQL was installed with the help of yum utility.
[root@oelserver ~]# rpm -qa | grep mysql
perl-DBD-mysql-4.012-1.el5.rf
mysql-server-5.0.45-7.el5
mysql-5.0.45-7.el5
mysql-5.0.45-7.el5

So, you've got an Oracle version (Carthage) of RHEL 5 (Tikanga).
Anyway, as this is an install and you're getting a bad shutdown => corrupt DB, TBH, I'd yum remove MySQL and then yum install it again.
Trying to fix it is more trouble than it's worth, unless you've already put substantial data into it and don't have a backup.
Just mho.

I already had tried with removing and reinstalling mysql-server packages twice (once with "rpm -e" and second time i did "yum remove")
Not had any luck with that

If you're getting that error on first time DB startup after installing, it suggests a bad CD/DVD.
If Oracle has online repos (I'd guess so) then install it from there instead.

I am installing from Oracle's online repos only using,
yum install mysql-server
and it downloads 3 required packages without any error

Installed: mysql-server.x86_64 0:5.0.45-7.el5
Dependency Installed: mysql.x86_64 0:5.0.45-7.el5 perl-DBD-mysql.x86_64 0:4.012-1.el5.rf
Complete!