Just to let you know that I'm still getting exactly the same thing against both a 2013 preview account and a 2013 developer account (using access 2013). If I try to create a web app through access it eventually times out with a "an error has occurred" message although the app does appear in Sharepoint but with error "Sorry, something went wrong with adding the app". Clicking on Install errors for the app - I get the same error as Lawrence:
There was a problem accessing the app's database.
Details: Secure Store Service did not performed the operation.
This is definitely an issue with the 365 service at the moment - I get the same message when trying to add an Access 2013 app from within sharepoint.
Regards,
Andy