what i found the solution was to note down all the apps that are giving this error...
then uninstall them one at a time
(if you do have an SD card, ensure that storage sense option says to install the app to the phone - some of these apps wont install on SD)
then go back to store and search for the app - if you dont find it with the simple name, use Bing xxxx - it still seems to find it -
there you go... should work now.