PHP PDO connecting to SQLITE db

So this morning I try to connect to SQLite database using PDO and also create a table. Firstly, I create a file called db.sqlite, and then create my connection and execute a create table query, but the execute pdo function always returns false.

$pdo = new PDO("sqlite:db.sqlite");
$STH = $pdo->prepare(
'CREATE TABLE "users" (
     "id" INTEGER PRIMARY KEY  AUTOINCREMENT  NOT NULL , 
     "full_name" VARCHAR, 
     "description" TEXT, 
     "token" INTEGER);
    ');
 $STH->execute();

So what I did next is to remove the db.sqlite from the connection and replace with :memory: to create a db in memory, which works perfectly.

$pdo = new PDO("sqlite::memory:");

So I am confused, why can I use :memory: and not the file, and how do I fix it?