Similar problem. New purchase and install of 3.3 went on a Win10 machine with IE 11 (no choice, it's that or nothing with Win10 unless you want to start frogging around with virtual machines). Worked well enough for about 4 or 5 days. Set up tourneys, players db, various templates, added events, ran through several tourney simulations... starting, busting players out, pausing, balancing & collapsing tables, etc., etc. Today "my load button stopped working"... in fact, all(?) of the buttons to load, save, save as, browse, etc. stopped working. I COULD start directly from one of my .tdt files, but couldn't modify and save my changes, etc., etc.
Have communicated with "support". Have downloaded and installed 3.4.b3. All appears to be well... so far. Hope it werkz!