First of all we have not tested with the PAP2-NA. However from the images and logs:
It seems your PBX is pbx.sistematica.com.br, however when i see the configured proxy in the Linksys PAP adapter, it lists the hostname of another machine.
The log shows that the call was received by 3CX Phone System and then forwarded to your VOIP Gateway. The VOIP Gateway then returned a 404 not found, meaning it could not dial the number 30132101. So the configuration between Linksys and 3CX Phone System is correct and the call is correctly handled by 3CX, however the LInksys can not dial the number and thus returns a 404 not found.
Check that the LinkSYS actually can detect an outbound line and that you can make calls from it. Check that the number is valid. Check that the Brasilian PSTN line settings are configured correctly and so on.