firewall initialize error corrupted configuration

Hi you all.

I’m new to Linux firewall and i chose Trustix enterprise for my 100 users network, we currently use pineapp machine

All the installation was seem ok, but when i tried to log in from the windows based client i get the same error

“Firewall initialize error corrupted configuration”
And after that the error
“Firewall misconfigured. No network device is set as lan device”

I understand that something is wrong in the configuration but what?

I tried playing with the network defines and still nothing.

Can someone help? / knows the subject

Firewall motherboard is
Currently only on board lan
*I know i should use at least 2 lan cards but I’m in Equatorial Guinea Africa and its on his way to me by shipment

Thanks in advance for your help