Interestingly enough I've been doing some digging (I'm also a software man! @Burim) and with the stocks that have problems they exist for any periodicity down to 1 min. If I select 10 secs or less it's okay (although, of course, you can only see a relatively short period of history) unless I select tick and then it just seems to hang. So at least I can select 10 secs and get some idea of current movements. Any periodicity above that doesn't work.
And you're correct; as I'm evaluating I am, indeed, using the demo platform. But it's not much of a demo if it doesn't work.