i have this issue when installing stuff. I just had it recently as i tried to update my CCleaner.
when i click cancel the download, it left me with the window below and unable to proceed further nor going back.
Tried googling it with no luck. Hopefully someone know how to solve this?
i tried reinstalling windows installer and java with no luck.
Similar problem found when i click AMD Home on my ATI CCC. as below.
Similar problem on Sopcast too.