Hi Antonio, no you are not doing anything wrong. You must understand that the security enhancements to v2 were a quantum leap over v1.9 and this threw up a whole range of unexpected issues and one of them was the backup/restore process. The difficulty of developing a solution was greater than anticipated so it can, currently only bring over course materials. At the MoodleMootAu in Sydney a week ago, Martin D said that the restoration of users and user materials was on track and would be expected to be included in the next version, that is 2.3 to be released in November.
It is possible to bring it all up to v2.1, and that is to upgrade your current Moodle the same way as you upgraded previous versions. The issues there have mostly centred around non-core blocks and filters though.
If you want to start with a clean install, a vanilla install I think the latest jargon is, then you create a new v2.1 and bring your courses into it, which is what you seem to have done. Best bet here is to wait until the end of your academic year and have it all prepared to go, so that all of your courses are active in your new Moodle but without any enrolments. Enter your students as required when when needed or do a bulk upload of all enrolments and Teachers can sort it. Most of the institutions I have spoken to are doing this beginning next December in the southern hemisphere and June/July in the northern - but by then, the whole restore package will be available, so it can be done any time.