I get the error a lot too. I demand a refund if he's getting one!

Joining the bandwagon. Lol.
The loss clearly didn't bother you or you would have complained at the time.
You said it it is a known problem, and other people didn't come here and want btc back like you.
I have been playing at primedice very regularly for the past few months. I'm shocked that they seem completely unwilling to help considering an error on their site almost certainly made me lose all my btc.
It didn't almost certainly cause you to lose it, but that's what your blaming the loss on. You could've just as easily have won, but you didn't. That's the gamble. He's not just going to give money back to everybody who is sore and complains after a loss.
Can you prove this? No, because the error affected the outcome.