There is definitely some sort of bug, I deposited 0.5 and my account got credited 2 BTC as well and I was able to withdraw, Lazlo PM me so I can send these back to you, you need to fix your site!
Thank you very much for your honesty sir you are a gent. We did lose some coins while I was offline though, really considering taking down the site all together and buying a better script.
Lazlo