Requested extension com.adobe.ane.productStore could not be found

I have a FLEX Mobile project.  I have tried several FLEX and AIR SDK.  I am currently using FLEX 4.6.0 and AIRSDK 15.0 that I downloaded from Adobe.  I have added "Product Store.ane" to my build path.  The ane file was downloaded from Adobe as part of Adobe Gaming SDK 1.4.  I can import com.adobe.and.prodictStore in my actionscript code.  My application description file contains the following:

<extensions>

        <extensionID>com.adobe.ane.productStore</extensionID>

</extensions>

Why do I get the Requested extension com.adobe.ane.productStore could not be found error when I try to run my application?

Thanks.