cant open multiple instances of max

so i have in the past used one patch for gui objects and one patch for the video effects and gl engine of my programs and open them as separate instances to keep the schedulers separate between onscreen graphic controls and loading schedules. for some reason now I cant open a second patch from explorer in windows but I can open them if I choose open from the file menu in max. when i double click a file to open it, it seems to immediately crash because it never opens and never gives any dialog why or anything. when i open the same patch with the menu it opens right up and there is no residual slow down that would suggest something hung up in the background. This obviously thwarts the advantage of multiple instances and that is a huge need for me with the level of video I am trying to run even if I offload the video processing of control objects onto the lemur, i still need my cueing system to be separate from the engine patch. Anyone else experience this before? Is there some max setting that I changed and dont remember that would prevent multiple instances?

thanks guys!

B