I have standard on my desktop and home machines and both were working fine with version 4 until I installed the latest adobe updates... then I had the same issue of all imports opening in their own window. I uninstalled reader and reinstalled reader version 9 and it started working normally again. I think the catch is that I had reader originally on both machines and added standard later - AC likes reader. There is another thread on a similar issue even with the current version :
http://www.amazingcharts.com/ub/ubbthreads.php/topics/9868/Problem_with_Acrobat#Post9868
