Just so you know, I don't think it's a fork, it looks like the same issue H2O coin had on their last launch where 32 bit clients get a rounding error and can't match the hash and nonce.  Something JP will have to fix in code and recompile wallets for.  There will be a fork if people are mining to a 32 bit client though, so make sure you are mining to a 64 bit build you have built yourself on linux or a pool that is using 64 bit.  If you solo mine to the windows wallet any blocks you may find would be on a fork.