I know this is not an answer to your question, but Ultiboard automatically places vias for the autorouting and it it couldn't find a path (based upon your description) then you probably are not going to be able to manually route it. I have run into this before. What I had to do is find which net was giving me the problem and try to place the component in a different location and try the autorouter again. Most of the time it works.
If you think you can manually route it the try the "Follow Me" tool or the "Connection Machine Tool" after placing your vias and see what happens. When I tried this on a test, the trace avoided the via like the plague and would not connect up to it and I don't know why even after assigning a net to it. This last thing may be a bug that needs to be addressed if we are both doing it right.
