The Prefs folder, I found out, is hidden by default in Mavericks.
Make sure you find it by opening a Finder window, then clicking Go>Go to Folder, then in the dialogue, enter ~/Library/Preferences and delete any Helicon entries that you find there.

Just to follow-up, I finally found the *hidden* Preferences folder and deleted the prefs files, which did fix the problem.
Thanks all for the help.

Hmm. Done that now but still crashing..
Any more suggestions?

Stas?

I have the same problem. How do you find and delete the preferences file?
(Also, Stas, if you're reading this, our old issue is still unresolved!)
Thanks