A Database Error Occurred Error Number: 1054 Unknown column 'Array' in 'field list

I got it fixed as earlier it was adding array to the database which was causing the problem where $data is array. Earlier the code was
if($msg=$this->Calibration_model->add_calibration($data)) {
$this->load->model('Logger_model');
$this->Logger_model->write($this->session->userdata('username'),"Add Calibration",$msg);

But now I have changed the code to add string instaed of array
if($msg=$this->Calibration_model->add_calibration($data)) {
$this->load->model('Logger_model');
$this->Logger_model->write($this->session->userdata('username'),"Add Calibration",$msg['msg']);

Now, its working fine . Thanks for your help.