After install DBD:mysql, perl still can't connect to mysql

hi,

I installed DBI, DBD:mysql, but when i use perl for connecting to mysql, some error has been occured. 

install_driver(mysql) failed: Can't load '/usr/lib/perl5/site_perl/5.8.8/i386-linux-thread-multi/auto/DBD/mysql/mysql.so' for module DBD::mysql: /usr/lib/perl5/site_perl/5.8.8/i386-linux-thread-multi/auto/DBD/mysql/mysql.so: undefined symbol: __pure_virtual at /usr/lib/perl5/5.8.8/i386-linux-thread-multi/DynaLoader.pm line 230.
 at (eval 4) line 3
Compilation failed in require at (eval 4) line 3.
Perhaps a required shared library or dll isn't installed where expected
 at first.pl line 6

My perl page : first.pl
#!/usr/bin/perl -w
use CGI qw(:standard);
use CGI::Carp;
use DBI;
$conn = DBI->connect('DBI:mysql:db_asterisk','root','');

It always errors at $conn = DBI->connect('DBI:mysql:db_asterisk','root','')

Please guide me to install that perl can connect to mysql


Best regards
QTuan