I added the same lines in my perl program . 

BEGIN {
  unless ($ENV{BEGIN_BLOCK}) {
    $ENV{ORACLE_HOME}     = '/usr/local/lib/instantclient_10_2';
    $ENV{LD_LIBRARY_PATH} = '/usr/local/lib/instantclient_10_2';
    #$ENV{TNS_ADMIN}       = '/common/oracle/env';
    $ENV{BEGIN_BLOCK} = 1;
    exec 'env',$0,@ARGV;
  }
}

I am getting the below error message
 
 env: this is not a file and directory

Please help