I have a couple of apps that give a "not found: The requested item could not be found" error when I try to update or view them in "my apps" in the market. (PDA Net is one of them). If I do an auto update (update all) the update process tends to hang when it gets to either of them. I still have the apps on the phone, and they work fine but I can't even get to the screen where I would turn off auto-updating for them. What can I do?
You will not be able to update them, they have been pulled from the market by either the developer or by google. PDA Net for example was recently pulled by google. You could see if the developers offer an alternative means to download, either from their website or a 3rd party market, like amazon app store. Then remove then from your device so they no longer appear in your google market. Then reinstall them via the 3rd party market, or by "sideloading" them.