Binding insert "fail" on execution

Welcome,

I have following table

Field               Type               Null  Key    Default     Extra
topic_id            int(10) unsigned   NO    PRI    NULL        auto_increment
topic_uri           varchar(255)       NO    MUL         
forum_id            int(11)            NO    MUL     0   
topic_title         varchar(255)       NO            
when                int(11)            NO           开发者_运维百科0    
topic_posts         int(11)            NO           0    
first_post_user     varchar(32)        NO           0    
first_post_when     int(11)            NO           0    
last_post_user      varchar(32)        NO        
last_post_when      int(11)            NO           0    
topic_sticky        int(11)            NO           0    
topic_locked        tinyint(4)         NO           0    
topic_hidden        tinyint(4)         NO           0    

I want make INSERT, using PDO binding.

$b=$dbh->prepare("INSERT INTO `mybase`.`bx_forum_topic`  (`topic_id`,`topic_uri`,`forum_id`,`topic_title`,`when,topic_posts`,`first_post_user`,`first_post_when`,`last_post_user`,`last_post_when`,`topic_sticky`,`topic_locked`,`topic_hidden`) VALUES (NULL,:topic_uri,:forum_id,:topic_title,:when,:topic_posts,:first_post_user,:first_post_when,:last_post_user,:last_post_when,:topic_sticky,:topic_locked,:topic_hidden)");

$test=12;
$b->bindParam(":topic_uri",$test);
$b->bindParam(":forum_id",$test);
$b->bindParam(":topic_title",$test);
$b->bindParam(":when",$test);
$b->bindParam(":topic_posts",$test);
$b->bindParam(":first_post_user",$test);
$b->bindParam(":first_post_when",$test);
$b->bindParam(":last_post_user",$test);
$b->bindParam(":last_post_when",$test);
$b->bindParam(":topic_sticky",$test);
$b->bindParam(":topic_locked",$test);
$b->bindParam(":topic_hidden",$test);

$b->execute();  
 print_r($dbh->errorInfo());


 echo $dbh->errorCode();

It don't show ANY ERROR. Error table shows Array ( [0] => 00000 ) 00000, but no data going inside my table.

When I use without binding:

$b=$dbh->prepare("INSERT INTO `mybase`.`bx_forum_topic` (`topic_id`, `topic_uri`, `forum_id`, `topic_title`, `when`, `topic_posts`, `first_post_user`, `first_post_when`, `last_post_user`, `last_post_when`, `topic_sticky`, `topic_locked`, `topic_hidden`) VALUES (NULL, '12', '12', '12', '12', '12', '12', '12', '12', '12', '12', '12', '12')");

$b->execute();  
 print_r($dbh->errorInfo());
  echo $dbh->errorCode();

It's working.

Where have I made a mistake? Why does it fail and not show any error with binding?

The problem is here I think:

`when,topic_posts`