Error 0x80073cf9 when installing or updating apps from windows store

On my Windows 8 desktop I keep getting error 0x80073cf9 when I try to install or update an app from the windows store.

In the installings apps pane it just says "This app wasn't installed -- view details" and when I select that it says "Something happened and this app couldn't be installed. Please try again. Error code: 0x80073cf9"

I am using the built-in windows firewall and antivirus. And my laptop is able to install updates when it is on the same network.

This is what winstore.log shows when I try to update the maps app:

2012-10-18 15:31:47.328, _Info_                WS   [00015160:00011628] ***********************************************************************
2012-10-18 15:31:47.328, _Info_                WS   [00015160:00011628] Process name: C:\Windows\system32\taskhost.exe
2012-10-18 15:31:47.328, _Info_                WS   [00015160:00011628] User name: Desktop\User
2012-10-18 15:31:47.328, _Info_                WS   [00015160:00011628] Computer name: desktop
2012-10-18 15:31:47.328, _Info_                WS   [00015160:00011628] Windows build: 9200.16424.amd64fre.win8_gdr.120926-1855
2012-10-18 15:31:47.328, _Info_                WS   [00015160:00011628] Client version: 615
2012-10-18 15:31:47.328, _Info_                WS   [00015160:00011428] CWSTileUpdateHandler::Worker: Broker is handling badge updates.
2012-10-18 15:31:47.554, _Info_                WS   [00002572:00008200] CProgressDispatcher::OnProgress: AppId = 97a2179c-38be-45a3-933e-0d2dbf14a142, PFN = Microsoft.BingMaps_8wekyb3d8bbwe, InstallPhase = 1, PhasePercent = 0, TotalPercent = 0
2012-10-18 15:31:47.558, _Warning_             WS   [00002572:00008200] CDownloadProgress::IDownloadCompletedCallback::Invoke: Download complete result 0x80073cf9 for Microsoft.BingMaps_8wekyb3d8bbwe
2012-10-18 15:31:47.559, _Error_               WS   [00002572:00008200] CActionItem::_DoDownload: Download failed for 97a2179c-38be-45a3-933e-0d2dbf14a142, hr=0x80073cf9
2012-10-18 15:31:47.560, _Info_                WS   [00002572:00008200] CActionItem::_DoDownload: Notifying progress handlers of download failure for 97a2179c-38be-45a3-933e-0d2dbf14a142, hr=0x80073cf9
2012-10-18 15:31:47.560, _Error_               WS   [00002572:00008200] CProgressDispatcher::OnError: PFN = Microsoft.BingMaps_8wekyb3d8bbwe, InstallPhase = 1, hrError = 0x80073cf9

Answer

Not sure how it could have happened, but this seems to be a possible solution:

The problem is that the folder AUInstallAgent is missing from the Windows folder. I had this problem, recreated the folder and low and behold all is working fine. Now what I want to know is why the folder disappeared in the first place, because I didn't delete it, and looking around the web I'm not alone....