spore galactic adventures

i have this same problem. what can i do?

\

You need Spore first as Galactic Adventures is an Expansion Pack

I have retail version installed and played it.  Still says you must have SPORE.  I have unstalled and reinstalled the spore and expansion won't install.  I have reinstalled whole OS!  Clean OS and still expansion say "You must have SPORE installed to install  SPORE Galactic Adventures."  I HAVE INSTALLED AND SPORE WORKS FINE.  JUST NEED TO INSTALL THE EXPANSION!!!!!