Its important to know that the FatPipe License is based off the eth0 (LAN) MAC Address.
When adding a PCI Card, typically the first or only port of that additional NIC get's enumerated first by the Bios therefore the eth0 MAC Address is different and the License is invalid.
The original IP Address configuration is still there, however disabled. Therefore, you are unable to get an ICMP (Ping) reply from any of the interfaces that you suspect might still have an IP Address configured.
You will need to call into the Support line before adding the New NIC, and be prepared with a keyboard and mouse to plug into the FatPipe Directly.
FatPipe Support will then instruct you through the Root Console and Re-Order the System NICS.