Hi

You have some syntax errors like the following

strOk = 'ok';
strNo = 'no';


This is not allowed it should have been

strOk := 'ok';
strNo := 'no';

The colon was missing

and some temporary variable definition has to be done

when ever you get some error at the sql prompt type the following command

SQL> Show errors

the above command will show errors

Hope this helped if you still have problem continue posting Iam sure we will be able to help

Regards