Jonathan,
The problem is on your side, the developer of wp robot states that the error message I am getting is from the thebestspinner api.
Wprobot does not generate this error message, Error: Invalid username or password. I wrote a script and ran it from my public_html directory and the wprobot plugin directory. In both cases it was able to load your thebestpinner.com and the /api.php site.
Jonathan, get off your butt and fix the script. I guess you are too busy counting your money!!. While my business goes down the drain.
thanks.