This sounds like a really major issue. I have not received this though. If someone can give me more details about this error I will try my hardest to fix it.
If you get a 'Oops' page, then this means that the URL you are visiting does not exist. This should not happen when posting, as ALL the files involved with this process already exist.
My conclusion is that the Server load is quite high (due to having a **** host), so when you go to post and the server load is high, the file isn't found. We are in the process of purchasing faster dedicated hosting in Sydney to make The Kennel 10x faster.