Do not feel bad, a lot of MM users make the same mistake, me included. Each MM version is a StandAlone version and not really an Upgrade, as such. True, you may be getting more and different stuff , Magix wants to sell its products....but sometimes they take other stuff away. You may have bought it on MM2010, but you ain't got it on MM2013....in the past Magix has said that some programs are transferable....maybe...theywon't say which ones, but in any case they say the transfer is not supported by Magix, you may try it, but you are on your own. Be glad they don't make you buy the same soundpools over and over. In the future, download the 30 day freebie and make sure its got what you want.
Did you notice you had posted to a thread which is more than 7 years old? Please do not resurrect such old threads but please start a new thread with full details of your system (see this post for details of what we need to know) along with the full version number and variant of MM which you have.