According to Intuit, Error Code c=0 can occur when attempting to access the Internet Connection Setup. This is function on the Help->Internet Connection Setup menu selection to configure your internet connection.
It’s caused by an outdated version of wininet.dll, a Microsoft Windows component. The solution is to either update this file, re-register it, or re-install Windows Internet Explorer.
For more information on resolving Error Code c=0, consult this Intuit knowledge base article.