Can not get required info from 'caller' at 'DB::sub'

http://paste.scsys.co.uk/502483

 Also it is strange to see the DB::DB is called twice for t3.pl (Notice the line 82, 85 at the paste)
The twice call does not occour if I remove 'caller' from t3.pl:4. Like: print 'FROM:';

The output:
...
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
t3.pl:9    	my $x =  3;

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
t3.pl:11    	t();
SUB: main::t - 
FROM: main - t3.pl - 17

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
t3.pl:4    	print "FROM";
FROM
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
t3.pl:13    	$x++;
3
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
t3.pl:18    print $x;