A friend of mine said it means something along the lines of "go being lightening" but I forgot exactly how she had worded it. And I tried putting it in a free translator, and it said something about lightening as well.
I'm French and "va te faire foudre" is not a proper French expression, it just does not exist. However, what was probably meant was "vas te faire FOUTRE", with a T, and that would be the equivalent of "f**k you".
I agree with Sensitive Girl, she's definitely right.
And Estella, if you read the responses in that link you found you'll see that they're all replying as if it said what Sensitive Girl translated it to. And if you can't understand french then you can at least see the very last response where someone just says "foutre?" clearly pointing out the mistake. ;-D