Can I update an app using the .xap file?

[Umang Khandelwal]

I am trying to update xbox music for windows phone. I don't want to do that using my cellular data. So I downloaded the .xap file and transferred it to the sd card. When I tap on "install local apps", I can see the xbox music app there but when I tap it, it refuses to download the update and I get a technical error with a code 80070057.
I also tried updating other apps using the same method but I keep on getting the same error. However, I am able to install a fresh app using the same method (using .xap file)