Wondering if anyone else has seen this problem and if it might be due to version 3.3.0, since there are posts in this thread of folks running multiple usb erupters with a raspberry pi.
It can be done, here is another screenshot for you;-

That's 1 x BFL Jalapeño (VERY old version) running alongside 9 Block Eruptors. I have heard that there has been stability problems with the AMU driver (even the cgminer authors say that there might be) but I have always been curious as to why MinePeon does not appear to be affected.
Is there any chance I could convince you to download MinePeon and see if it makes a difference?
Neil