That's the exact same behaviour I find, once the program has crashed.
Only problem is: it doesn't go away after the first install. If I make an error addressing the .DLL (and since the expression is evaluated immediately, it could be as much as a typing error...) the program crashes and I have to ...

Okay, seems like an error in a .DLL triggers the fault.
Solution: Uninstall flowstone, then re-install. (after killing the processes in memory..)
It also uninstalls all saved programs in the workfolder, so SAVE THESE SOMEWHERE ELSE...
I hope this is still beta-software...

Well... I seem to have a problem that looks identical.
Installing went fine, but after playing around for an hour, the program crashed out and won't start now, showing the symptoms mentioned above.
Re-starting, re-installing or re-downloading doesn't help...
Any suggestions?