Exporting to an APK has a form you have to fill in with settings that have to be correct.
If you download the latest version of GiderosMobile (2016.12 and applied the patch 2016.12a) then boxes 2 and 3 should be left blank as the export tool can figure these out.
Box 4 should be set to 22 as this is the highest API that Gideros currently supports.
But boxes 5 and 6 may be a bit of a mystery to you. So...
Here is a Christmas Helper for you that will help you enter the correct values into these two boxes!