by Robert Brenstein.
I concur with others that you should go from 1.9 to 2.2 then to 2.6, or 2.7 if your server allows for that, at the end. That is actually documented somewhere. I want to add that there is a known technological discontinuity when switching from 1.9 to 2.x, so your experience is not a surprise. A number of modules do not transfer cleanly at least for some people. Some modules can't transfer content at all and need to be basically recreated in 2.x. Some modules that were in core are no longer there. It is basically a trial-and-error game. A good backup is critical. It is usually a good idea to keep the 1.9 site running and get the 2.x running in parallel.