Bad extension for file once we run COM class

Please help to find out solution for this problem

i am running DLL file using php class COM in laravel 5 , my code given below ,

trying with fully path of dll :

use \COM ; (Include top of my controller as well )

this line of code under my function

$obj = new COM('C:\Windows\Microsoft.NET\assembly\GAC_MSIL\EntraPassUtility\v4.0_1.0.0.2__ecc8607640d67af4\EntraPassUtility.dll');

Showing error : Bad extension for file

Failed to create COM object `C:\Windows\Microsoft.NET\assembly\GAC_MSIL\EntraPassUtility\v4.0_1.0.0.2__ecc8607640d67af4\EntraPassUtility.dll': Bad extension for file

via Chebli Mohamed