Sounds like Application Loader 3.2 has some sort of issue that Apple will need to fix.
I’m not suffering from the issue but it’s possible that removing your Application Loader preferences might help (you’ll have to re-enter various things like your username and password). In Terminal run this command:
defaults delete com.apple.itunes.connect.ApplicationLoader
If you’re running Application Loader manually (as some people have to do for a variety of reasons) then these kind of errors are outside Corona’s control and should be reported to Apple. Not that submitting apps directly from the Simulator may be any better since the Simulator depends entirely on Application Loader which is quite flaky.