Hi Andrej,
I remember when we upgraded our mx6 project to mx7 we intentionally skipped 7.0.2 and went straight to 7.1.0. I don't remember the exact details but there were some known bugs that were fixed in 7.1.0 and 7.1.1.
Also I've run into some issues in the past with the community commons library throwing build errors. Usually in the error you can see what java action is throwing the error and remove it if its something that you aren't using.