Looks like repreparing a statement without closing it 
makes some problems -> assigned (tested against 
5.0.5-beta) 
 
The script itself works as expected - fetching a row 
without executing statement before returns an error. 

Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to report
a bug at http://bugs.php.net/how-to-report.php

Prepared statements return unbuffered resultsets by default,
therefore you have to retrieve all data or close the resultset before any command to the server.

The last statement doesn't work, cause MYSQL_TYPE_NULL is unsupported (filed as bug #32956).

this is not NULL or unbuffered resultset only...
try this:

Reproduce code:
---------------
$st = $db->prepare("SELECT 1.23 AS test");
$st->bind_result($x);
$st->fetch();
var_dump($x);

Expected result:
----------------
float(1.23)

Actual result:
--------------
...FATAL ERROR WITH NO OUTPUT...

or maybe floats are also unsupported ?..

Please try using this CVS snapshot:

  http://snaps.php.net/php5-STABLE-latest.tar.gz
 
For Windows:
 
  http://snaps.php.net/win32/php5.0-win32-latest.zip

php also dies with latest snapshot

Doesn't crash here (tested against PHP-5.0.5-dev and PHP-5.1.0-dev) and returns NULL as expected.

Please reread the documentation on how to work with prepared statements. It makes no sense to fetch a value from a prepared statement without executing it before.

Still crashes for me with latest 5.0.5-dev... Just forgot to write ->execute() in sample.
MySQL version 5.0.4 - may be this is important.

// This works
$db = new mysqli(...);
$st = $db->prepare("SELECT 1 AS test");
$st->execute();
$st->bind_result($x);
$st->fetch();
var_dump($x);

// This crashes
$db = new mysqli(...);
$st = $db->prepare("SELECT 1.23 AS test");
$st->execute();
$st->bind_result($x);
$st->fetch();
var_dump($x);

// This crashes too
$db = new mysqli(...);
$st = $db->prepare("SELECT NULL AS test");
$st->execute();
$st->bind_result($x);
$st->fetch();
var_dump($x);

Your example is broken - you don't call execute() on the prepared statement object. However, this reveals another problem - whenever a unbuffered query is used (mysqli_stmt_store_result not called) the wire has to be cleaned before the next prepare. One call to fetch() does not help.