Lots of people have this issue...I see no consistent solutions. I want to share my research:

First of all, many people think this has to do with HP's servers being overloaded...maybe at times, but I haven't gotten into the app store in 2 weeks.

One theory is that it has to do with the most recent version of the App Store software, which you can revert by using preware to delete it, and then restart the device. Read about it here: HP webOS App News

One person said they got some advice from a tech, where they did a backup, erased their profile, then restored it. This updated their purchase info, which fixed it. Look here: http://forums.precentral.net/hp-touc...ml#post3240209

Another person seems to think the hulu patch is breaking things, look here: http://forums.precentral.net/hp-touc...ml#post3241018

As for me, none of this helped me out. Nevertheless, I've got some more information. When I was going on to backup the device, the backup app failed for me. After clicking "Back Up Now," it prepares for a bit then fails. While that is working now, it made me go and install "Save/Restore" and when I tried to use that, I got the following error when trying to back up Memos, Messaging, and tasks: "Error: unable to open database "/var/luna/data/dbdata/PalmDatabase.db3": unable to open database file."

I used Internalz to browse to that folder....there isn't even a dbdata folder. I think somehow this got corrupted, so I'm gonna doctor tonight. I just wanted to share my research in 1 spot on all the different possible solutions people have suggested.