They have some info on their support page... but not all that helpful. "iPhod"
If you can not install or upgrade to version1.2, upgrade your iPhone and iPhod touch OS, or please contact Apple side
9. I got the download error Message during installing/upgrading
Before you installing and upgrading, you must upgrade your device to O.S.2.2.1. But if it is not working after that, the error during installation is the problem of APPLE server or network. If there's any problem during operating the application after downloading whole application, it can be application problem.
Accordingly, any error during downloading should be asked to App store side.
For your reference, even the 1st downloading was failed, however, once you connect to the network again, the downloading will start automatically again.
11. ITunes reports not enough space to install.
Since our application is under 3GB, it should be downloadable.
We suppose it's APPLE's server problem. For getting exact solution, Please, kindly contact APPLE side. At the same time, we'll also do the same test and ask to APPLE directly as well.
http://www.xroadgps.com/Maps/GMapforiPhone/FAQs/tabid/2497/Default.aspx#14