Either it is or it is not.

Two possible reasons for running across the "error: Error parsing XML: unbound prefix" issue on building your Android app.

1)  You have not properly specified an XML namespace for Android to use.  Fixing this is easy, just add

"
xmlns:android="http://schemas.android.com/apk/res/android"
                                              "

immediately after the opening of the first LinearLayout tag at the top of your document.  This will allow the interpreter to parse the rest of your document and recognize the android: properties.

2)  You have an error in your XML that is very likely a spelling mistake.  When I was searching for this I was confused because it repeatedly specified the opening of the XML tag which was on a seperate line from the actual misspelling.  I had to go down three lines to where I had specified andriod:id rather than android:id.

Hopefully this helps someone!  :)