codeingiter 1.5.4 and EXTJS 2.0.1

[eluser]Yauhen_S[/eluser]
This code looks good, but is not solving problem with PHP errors handling. By default CI return HTML error message, for example if db error occur. And ExtJs cause error when evaling response text. I was try to replace CI errors templates like this:

<?php
$res = array(
'success' => false,
'errors' => array(
'heading' => 'PHP Error:',
'message' => "<p>Severity: $severity; ?&gt;</p>
<p>Message: $message</p>
<p>Filename: $filepath</p>
<p>Line Number: $line</p>"
)
);
print json_encode($res);
?&gt;

but this work if only one error occur, otherwise output come incorrect JSON code