The 2 class upgrades you have chosen (Wizard to Warlock, and Fighter to Barbarian) are both good moves, and ones that have no serious downsides for making early. As a Warlock, there are no penalties to learning Sun and Stone magic so I think this move is well worth it. Moving a fighter to barbarian is just a good quick way of gaining lockpick skills if you didn't waste space in your party by starting with a rogue. Sorry, but I have no info to offer on your crash problem - haven't heard anything similar discussed before.
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