my $ORACLE_HOME = "/opt/oracle/app/oracle/product/10g";
my $ORACLE_SID1="DBHOSTNAME";
my $TGT_USER="USER1";
my $TGT_PASS="PASSWORD";


$ENV{ORACLE_HOME}=$ORACLE_HOME;
$ENV{PATH}="$ORACLE_HOME/bin:/usr/sbin";
#$ENV{LD_LIBRARY_PATH}="$ORACLE_HOME/lib32";
#$ENV{CLASSPATH}="$ORACLE_HOME/JRE:$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib";


BEGIN {
    die "ORACLE_HOME not set\n" unless $ENV{ORACLE_HOME};
    unless ($ENV{OrAcLePeRl}) {
       $ENV{OrAcLePeRl} = "$ENV{ORACLE_HOME}/perl";
       $ENV{PERL5LIB} = "$ENV{PERL5LIB}:$ENV{OrAcLePeRl}/lib:$ENV{OrAcLePeRl}/lib/site_perl";
       $ENV{LD_LIBRARY_PATH} = "$ENV{ORACLE_HOME}/lib32";
       exec "$ENV{OrAcLePeRl}/bin/perl", $0, @ARGV;
    }
}
use strict;
use warnings;
use DBI;
my $sql;
my $sth;
my $sql_ins;
my $sql_del;
my $sql_upd;
my $sql_com;
my $sth_ins;
my $sth_del;
my $sth_upd;
my $sth_com;
my $dbh_src;
my $dbh_tgt;
my $count_of_rev;
#---------------------------------------- common initialization block - end ----------------------#
print "Variable initialization block executed\n";
#---------------------------------------- Get Account id - Start ----------------------#
my $sh_name=$ARGV[0];
my @acc_row;

$ENV{ORACLE_SID}=$ORACLE_SID1;
$dbh_tgt = DBI->connect("dbi:Oracle:$ENV{ORACLE_SID}", $TGT_USER, $TGT_PASS) or die;
print "Connection Successfull\n";
$dbh_tgt->disconnect;



##</code><code>##

 $ENV{LD_LIBRARY_PATH} = "$ENV{LD_LIBRARY_PATH}:$ENV{ORACLE_HOME}/lib32:$ENV{ORACLE_HOME}/lib"; 

##</code><code>##

export LD_LIBRARY_PATH=$ORACLE_HOME/lib

Update: If you get an ELFCLASS64 error, try setting LD_LIBRARY_PATH to $ORACLE_HOME/lib32 instead.