fatal error format raised

( ! ) Fatal error: Call to a member function format() on a non-object in D:\xampp\htdocs\acc_career\protected\extensions\autodate\MdmAutoDateBehavior.php on line 64
Call Stack
#	Time	Memory	Function	Location
1	0.0006	143280	{main}( )	..\index.php:0
2	0.0175	1149384	CApplication->run( )	..\index.php:13
3	0.0175	1150008	CWebApplication->processRequest( )	..\CApplication.php:180
4	0.0192	1276976	CWebApplication->runController( )	..\CWebApplication.php:141
5	0.0218	1549912	CController->run( )	..\CWebApplication.php:282
6	0.0224	1578896	CController->runActionWithFilters( )	..\CController.php:265
7	0.0234	1631616	CFilterChain->run( )	..\CController.php:291
8	0.0235	1632680	CInlineFilter->filter( )	..\CFilterChain.php:130
9	0.0235	1632784	CController->filterAccessControl( )	..\CInlineFilter.php:58
10	0.0241	1688336	CFilter->filter( )	..\CController.php:1145
11	0.0293	1871736	CFilterChain->run( )	..\CFilter.php:40
12	0.0293	1871808	CController->runAction( )	..\CFilterChain.php:133
13	0.0293	1871856	CInlineAction->runWithParams( )	..\CController.php:308
14	0.0293	1872176	JobController->actionAdmin( )	..\CInlineAction.php:49
15	0.0545	3188936	CController->render( )	..\JobController.php:165
16	0.0545	3189048	CController->renderPartial( )	..\CController.php:782
17	0.0547	3189792	CBaseController->renderFile( )	..\CController.php:869
18	0.0547	3189888	CBaseController->renderInternal( )	..\CBaseController.php:95
19	0.0550	3215432	require( 'D:\xampp\htdocs\acc_career\protected\views\job\admin.php' )	..\CBaseController.php:126
20	0.0864	4881120	CBaseController->widget( )	..\admin.php:65
21	0.0878	4965928	WhDatePicker->run( )	..\CBaseController.php:167
22	0.0878	4966040	WhDatePicker->renderField( )	..\WhDatePicker.php:53
23	0.0878	4966320	CHtml::activeTextField( )	..\WhDatePicker.php:68
24	0.0878	4966768	CHtml::activeInputField( )	..\CHtml.php:1434
25	0.0880	4967168	CHtml::resolveValue( )	..\CHtml.php:2252
26	0.0880	4967272	CActiveRecord->__get( )	..\CHtml.php:2529
27	0.0880	4967400	CComponent->__get( )	..\CActiveRecord.php:145
28	0.0880	4967704	MdmAutoDateBehavior->__get( )	..\CActiveRecord.php:127
29	0.0880	4967960	MdmAutoDateBehavior->convertToLogical( )	..\MdmAutoDateBehavior.php:34