We have received several tickets reporting that Layar keeps downloading from Android Market but never ends. The cancel download button does not seem to work either. This is a known issue of Android Market instead of Layar App itself. This problem usually disappears after waiting for a while (several hours even).

Please see the troubleshooting explanation from CyanogenMod below:

"The login service that needs to run in the background in order for you to download, sometimes does not start. The service is shared between GTalk and the Market, GTalk being the responsible entity for starting the service. If your download isn't starting, manually login into GTalk, and that should fix the problem."

For more information, please visit http://wiki.cyanogenmod.com/index.php?title=Troubleshooting.