Cyclone IV Transciever Starter Kit Automation Issue MAX_error LED stuck on.

We have an automated test system running with Cyclone IV Transciever Cards acting as PCIe EP's.

Our automation system load the .elf to the card memory via a NIOS console running on a host PC.

The Host PC is on all the time , but the DUT is power cycled where the PCIe slot power is removed and

re-applied at times ... Is this legal ... since the Host PC is supplying +5V USB to the USB I/F device but the other

supplies to that device are off .... ?

At some time, unknown, the Cyclone card red LED , MAX_error comes on and will not clear when the power is

removed from the Cyclone card , unless the USB cable , supplying +5V USB is removed also.

I'm thinking the USB I/F device may be in some error state and will not clear unless the +5V USB power is removed .

With this information, does anyone have ideas on:

1. How what this condition is ?

2. How to avoid this condition OR clear this condition from the Host PC without shutting down the PC or removing the USB cable ?

Thanks, Bob.