So...what is the DDx for this situation?
1. They hate you.
2. They got halfway through your app and were laughing so hard at it that they couldn't take any more and stopped downloading it.
3. They started downloading and then, partway through, something happened on one side of the connection or the other and it didn't complete (the network choked, somebody tripped over the power cable, the IT drones forced an upgrade/restart on everybody's machine, th PC got bored forgot what was going on and shut down the computer mid-download, dingos ate your data).
It will get downloaded the next time someone logs on. Relax.