Works fine for me.
Program uses API to login so it can't really be compared with website login via browser.
Maybe you're using proxy in program and DBC doesn't like it? The "500" code seems like some server related issues (not username / password). On wrong user details it shows 403 code ("Forbidden").
From their FAQ:
Quote:
500 Internal Server Error if something happened on our side preventing you from uploading the CAPTCHA; if you are sure you're sending properly prepared requests, and your CAPTCHA images are valid, yet the problem persists, please contact our live support and tell them in details how to reproduce the issue
I would still suggest using Anti-Captcha, the setup is the same (you just need to enter access key from the website) and everything else is done on their side.