Using PDO and failing to insert a record

I am having a slight issue adding a record into the database.

For some reason it is not adding the record into the database.

I have a form in HTML and serialize it with jQuery to use in an AJAX request. I know this works as I used to use it with the old mysql commands.

This is what I have in the insert.php file:

$ln=($_POST['lastname']);
$fn=($_POST['firstname']);
$dob=($_POST['dob']);
$un=($_POST['username']);

$a1=($_POST['address1']);
$a2=($_POST['address2']);
$town=($_POST['town']);
$county=($_POST['county']);
$pc=($_POST['postcode']);
$country=($_POST['country']);
$lat=($_POST['lat']);
$lng=($_POST['lng']);

$lp=($_POST['landline']);
$mp=($_POST['mobile']);
$e1=($_POST['email1']);
$e2=($_POST['email2']);

$web=($_POST['web']);
$notes=($_POST['notes']);
$fb=($_POST['fbid']);
$tw=($_POST['twitter']);
$cat=($_POST['cat']);

$it=($_POST['Time']); 
$idate=($_POST['Date']); 
$iip=($_POST['ipaddress']);
$ib=($_POST['browser']);
$ios=($_POST['os']);

These are the posted values being used from the form.

I then have the following queries (I have 5 different ones as they are writing to 5 tables. As I say, this worked with the old mysql commands, but not the PDO commands.

$sqlp = $conn->prepare("INSERT INTO ".PERSON." (lastname, firstname, dob, adbkid) VALUES(:ln, :fn, :dob, :un)");
$sqlp->execute();
$idp = $conn->lastInsertId();

$sqla = $conn->prepare("INSERT INTO ".ADDRESS." (address1, address2, town, county, postcode, country, lat, lng, personID) VALUES (:a1, :a2, :town, :county, :pc, :country, :lat, :lng, :un)");
$sqla->execute();
$ida = $conn->lastInsertId();

$sqlc = $conn->prepare("INSERT INTO ".CONTACT." (landline, mobile, email1, email2, personID) VALUES (:lp, :mp, :e1, :e2, :un)");
$sqlc->execute();
$idc = $conn->lastInsertId();

$sqlm = $conn->prepare("INSERT INTO ".MISC." (web, notes, photo, fbid, twitter, cat, personID) VALUES (:web, :notes, :pic, :fb, :tw, :cat, :un)");
$sqlm->execute();
$idm = $conn->lastInsertId();

$sqlv = $conn->prepare("INSERT INTO ".VARI." (Time, Date, ipaddress, browser, os, personID) VALUES (:it, :idate, :ip, :ib, :ios, :un)"); 
$sqlv->execute();
$idv = $conn->lastInsertId();

$sqlp->bindValue(':ln', $ln);
$sqlp->bindValue(':fn', $fn);
$sqlp->bindValue(':dob', $dob);
$sqlp->bindValue(':un', $un);

$sqla->bindValue(':a1', $a1);
$sqla->bindValue(':a2', $a2);
$sqla->bindValue(':town', $town);
$sqla->bindValue(':county', $county);
$sqla->bindValue(':pc', $pc);
$sqla->bindValue(':country', $country);
$sqla->bindValue(':lat', $lat);
$sqla->bindValue(':lng', $lng);

$sqlc->bindValue(':lp', $lp);
$sqlc->bindValue(':mp', $mp);
$sqlc->bindValue(':e1', $e1);
$sqlc->bindValue(':e2', $e2);

$sqlm ->bindValue(':web', $web);
$sqlm ->bindValue(':notes', $notes);
$sqlm ->bindValue(':pic', $pic);
$sqlm ->bindValue(':fb', $fb);
$sqlm ->bindValue(':tw', $tw);
$sqlm ->bindValue(':cat', $cat);

$sqlv ->bindValue(':it', $it);
$sqlv ->bindValue(':idate', $idate);
$sqlv ->bindValue(':iip', $iip);
$sqlv ->bindValue(':ib', $ib);
$sqlv ->bindValue(':ios', $ios);

I have ran these with a try catch to see if I can figure out what is going on and I get the following error:

"SQLSTATE[HY093]: Invalid parameter number: no parameters were bound"

I have echoed out what is being put into each of the values and it corresponds with what I have in entered into the form.

I am also trying to echo out the last inserted ID's for each table and it isn't echoing that out.

I have had a look around Google and php.net and here and from what I read I am doing everything as they say I should be.

I am at a loss as to what is happening.

If you had any pointers they would be most welcome.