I have no idea what is wrong on your system. Put the iso up somewhere so I can download it and try. That is about the only way I can help you now. I'll actually have to take a look at it myself.
You can also try running ubiquity in debug mode to see what other messages it pops up.
Do me a favour as well, if you are going to ask ahgain about stuff like this please post your current status including the problem you are having. I don't have time to go reading old posts and I'm working on a pile of things at the same time so I have no idea what your original issue is.
If you post on my forum with a proper thread title that would make it much easier for me.
I solve the problem using --no-migration-assistant parameter for ubiquity.
Now I have a different problem:
I can not click "continue" button because it is always disabled on "choose a picture" step of installation.
The same iso does not asked "chose a picture" step on my desktop, but the same iso asks on my laptop