You've this one with short PCI slot, right?

i've same issue with my mrt when i disconnect all PCI cards and peripherals from the PC to do maintenance.

Then after i reconnect all the peripherals, including the mrt card, it gives me the same problems such as card identification error or incorrect serial number.
This happens especially when i attach MRT card on PCIe x1 slot, this because it is mechanically very instable, but when i connect it to PCIe x16 slot it is much more stable.
Once the card is properly inserted into the PCIe slot (check it by opening pc3k sw), lock it with the screw. Often this is another issue due to poor quality PC cases, this means that pc3k udma/mrt cards may seem a little crooked from the back side of the PC and the screw it will not help (or it can make it worse if you tight hard) because the card would not get aligned properly.
If this happens, you might want considering locking the metal bracket of your pc3k card (all your pcie cards) to your pc case with this type of vertical bracker

instead using the typycal screw that locks the card bracker to pc case.
That black vertical bracker with two screw on top and bottom worked very well for me.
I suggest also to clean you pcie slots and pc3k contacts.