This particular issue is caused by the EAX support for ASUS Xonar cards, scrapdogg is the 3rd person I've seen with this problem (confirmed in the ISBoxer chat room).

For anyone else, if you get this problem, until I get this fixed you can check the Task Manager process list for HsMgr.exe and HsMgr64.exe, kill them both and IS will launch sessions properly.

I am working on getting this fixed asap, along with a couple other rare issues that cropped up