I have this problem and I read the thread which seems to suggest that GSX and IvAP use the same hotkey (Cntl+F12). In my case, IvAP uses Cntl+F9 and GSX uses Cntl+F12 but once I load IvAP GSX stops working (or the hotkey Cntl+F12 stops working). I will try changing the GSX hotkey anyway to see if that works...