Fatal error: Call to a member function on a non-object

[prajataayu123]

Can anyone please guide me as to how to fix the below mentioned problem from php

...
Fatal error: Call to a member function on a non-object in /usr/local/apache2/htdocs/knowledgeTree-OSS/lib/browse/DocumentCollection.inc.php on line 414


/////////////////

The code is as follows...

function setSorting() {
    387
    388         $this->_sorted = true;
    389
    390         // defaults
    391         $this->_sDocumentSortField = 'DM.name';
    392         $this->_sFolderSortField = 'F.name';
    393
    394         foreach ($this->columns as $key => $oColumn) {
    395             if ($oColumn->namespace == $this->sort_column) {
    396                 $this->columns[$key]->setSortedOn(true);
    397                 $this->columns[$key]->setSortDirection($this->sort_order);
    398
    399                 // get the join params from the object.
    400                 $aFQ = $this->columns[$key]->addToFolderQuery();
    401                 $aDQ = $this->columns[$key]->addToDocumentQuery();
    402
    403                 $this->_sFolderJoinClause = $aFQ[0];
    404                 $this->_aFolderJoinParams = $aFQ[1];
    405
    406                 if ($aFQ[2]) { $this->_sFolderSortField = $aFQ[2]; }
    407                 $this->_sDocumentJoinClause = $aDQ[0];
    408                 $this->_aDocumentJoinParams = $aDQ[1];
    409
    410                 if ($aDQ[2]) {
    411                     $this->_sDocumentSortField = $aDQ[2]; }
    412                 } else {
    413                          /*   $oColumn->setSortedOn(false);*/
    414                                 $oColumn->setSortedOn(false);
    415                 }
    416         }
 

The problem is at line 414

[code green]

You need to pass this object into your function

$oColumn