If a command to create a region fails, what might have been wrong?

There was a gap or space in the shape

There was a gap or space in the shape>>>>>>>>>>>>>Thank you

the polyline is not closed 

Thank you for inviting me

I agree with eng. mohammed

I agree with mr Yacoub..............thanks

The object is not enclosed object.

The answer is ''There was a gap or space in the shape'' No more, No less. thanks