sorry for not writing execute there . I've created test scenario where I'm facing problem as shown below.I was able to resolve the problem by using do statement rather than prepare statement but could not figure out the reason behind it.

my $dbh = DBI->connect( "dbi:Sybase:server=$dbServer;hostname=$hostnam
+e; database=$ +database",$dbUser, $dbPasswd->[1],{AutoCommit => 1}); 
my $insertStatement = $dbh->prepare("INSERT INTO BatchFile (FileName,F
+ileStatusCode,FileDate,FileFormatCode,TotalRecords,LoadStartTime,Modi
+ +fiedDate,ModifiedBy) VALUES ('Akash',4,GetDate(),0,3,GetDate(),GetD
+at +e(),'FIX2MQ')") or $DBI::err and die($DBI::errstr); 
my $updateStatement = $dbh->prepare("UPDATE BatchFile SET FileStatusC 
++ode = ? ,ModifiedDate = GETDATE(),TotalRecords = ? WHERE BatchFileID
+ += ?"); 

for(my $x=0;$x < 5;$x++){ 
$insertStatement->execute() or die($DBI::errstr); my $id = $dbh->last_
+insert_id(undef,undef,undef,undef) or die "no inse +rt id $DBI::errst
+r $!"; print "ID : ",$id; update1($id); } 

sub update1{ 
my $id = shift; $updateStatement->execute(6,1,$id) or die($DBI::errstr
+); } 

$insertStatement->finish(); $updateStatement->finish(); my $rc = $dbh-
+>disconnect or die($DBI::errstr);
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From DBD::Sybase

The last_insert_id() call is simply a wrapper around a "select @@ident
+ity" query. To be successful (i.e. to return the correct value) this 
+must be executed on the same connection as the INSERT that generated 
+the new IDENTITY value. Therefore the statement handle that was used 
+to perform the insert must have been closed/freed before last_insert_
+id() can be called. Otherwise last_insert_id() will be forced to open
+ a different connection to perform the query, and will return an inva
+lid value (usually in this case it will return 0).
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Try adding ->finish()

for (my $x=0;$x < 5;$x++){ 
  $insertStatement->execute() or die($DBI::errstr); 
  $insertStatement->finish();
  my $id = $dbh->last_insert_id(undef,undef,undef,undef) 
           or die "no insert id $DBI::errstr $!"; 
  print "ID :",$id; 
  update1($id); 
}
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poj