checkboxes value gets stored as "array"

Hey and thank you for this awesome tool.

It's been working great until I added checkboxes in the fields. The column "sok" wich I changed from being a select gets the value "Array" in the mysql db. I dont remember when i downloaded the files but the .js says its version 1.22, the debugger code is "aqopos".

this is my response in firebug when posting my edit

<br />
<b>Notice</b>: Array to string conversion in <b>dataTables/php/lib/Database/Driver/Mysql/Query.php</b> on line <b>78</b><br />
{"id":"row_6","error":"","fieldErrors":[],"data":[],"row":{"DT_RowId":"row_6","process":"Verksamhetsstyrning","handling":"wertwer","sok":"Array","lagringsplats":"Dokumenthanteringssystem","bevaras":"7 \u00e5r","kommentar":"ererwt"}}

with this as post data

action edit
data[bevaras] 7 år
data[handling] wertwer
data[kommentar] ererwt
data[lagringsplats] Dokumenthanteringssystem
data[process] Verksamhetsstyrning
data[sok][] Upphandlingsnummer
data[sok][] Fastighetsbeteckning
id row_6
table

the last line in this code gets the error

protected function _prepare( $sql )
	{
		$this->_stmt = $this->_dbcon->prepare( $sql );

		// bind values
		for ( $i=0 ; $i<count($this->_value) ; $i++ ) {
			//echo 'Binding: {:'.$this->_field[$i] .'} as {'. $this->_value[$i]."}\n";
			$this->_stmt->bindValue( ':'.$this->_field[$i], $this->_value[$i] );

Does anyone have an idea what my problem might be?