The Spreadcoin wallet is pretty unstable. That's why I'm not keeping my SPR on there until they say we need to. It is safer on an excahange. My wallet went on a fork the first time I DL it. The dev said delete every file and reinstall was the only option. Since I hadn't backed it up yet, I would have lost all my SPR if I had already sent it.
So try to avoid using the SPR wallet.
I've never had a problem with it and have used it since launch with as much as 20 gpus mining to it and as little as 0. Anything can fork, but odds are you were mining to it when it wasn't in sync with the rest of the network or something was blockin/slowing the connection.
Anyways, wallet is fine, but I would recommend downloading the chain snapshot from the spread thread as it's an older coin with lots of history. Might have to go back a few pages in thread to find it though.