Need help for configuration mysql server

[Magpie]

Hi,

Recently I have upgraded mysql 3.23 series to mysql 4 series, however it does not works.
And output the error as shown:

[root@test downloads]# mysql_convert_table_format forum
install_driver(mysql) failed: Can't load '/usr/lib/perl5/vendor_perl/5.8.0/i386-linux-thread-multi/auto/DBD/mysql/mysql.so' for module DBD::mysql: libmysqlclient.so.10: cannot open shared object file: No such file or directory at /usr/lib/perl5/5.8.0/i386-linux-thread-multi/DynaLoader.pm line 229.
at (eval 11) line 3
Compilation failed in require at (eval 11) line 3.
Perhaps a required shared library or dll isn't installed where expected
at /usr/bin/mysql_convert_table_format line 37

Later on, trial and error, mysql4 series was being downgraded by my friend to 3 series.
And now it can't work anymore.

[root@test init.d]# ./mysqld start
Can't execute /usr/bin/mysqld_safe [FAILED]


Any mysql expertise can help me on this issue? Thanks alot!