There has been a lingering issue in the Android market when downloading updates to apps. You’ll see that an app update starts to download but it will never finish. It will sit there “downloading” forever, clicking cancel will cause the Market app to force close. It’s not isolated to Key Ring, it’s been happening with all apps.
Good news is that the fix is an easy one. You need to clear the contents of the download queue from the Android Market app. To do this click the following: Settings > Applications > Manage Applications > Market (path could vary slightly based on your build).
Once you are on the screen click “Force Stop” then “Clear Cache”. This will not impact any data in the Market (ratings,comments) nor will it impact your data in Key Ring.
Looking at this thread of comments the problem has apparently been going on for quite a while, though based on the emails we’re getting it seems to have been getting worse lately.
I’ll keep this post updated with other fixes people have had success with.
Some have reported that when the cache clear doesn’t work, clicking “Uninstall Upates” on the Market screen fixes the issue. This won’t clear your app updates, just updates to the Market app itself. The only drawback is that app updates will download in sequence instead of in parallel. Probably not that big of a deal, it’s better than no updates at all.
Others have had luck switching of 4G (on Evo) or switching off Wi-Fi, clearing the cache, and running the updates.