I would like to change Global Navigation so that all Site Collections within the Web Application will be visible, without changing or adding new masterpage, and publishing features are not enabled. thanks for advices.
If you want dynamic navigation i.e. a new site collection added should automatically be available in the navigation menu then you will have to custom develop this http://www.sharepointmechanic.com/?p=439
Other options include jQuery:
Or you can manually create links on the top navigation bar, but it would be tedious to maintain.
Regarding the error message, the solution was not tested with host named site collections so I'm not sure if it will work with those or not. The error message you're seeing indicates to me that you are missing a reference to your MyTestTopNavProvider in your masterpage.