Can Not See Files on the FTP

[MxxCon]

it seems like your router is performing NAT in the ftp session.
both of your screenshots show that your flashfxp is sending PORT command with the wrong ip..your internal one instead of internet one.
when connection is on port 21, your router changes your internal ip to internet ip.
when connection is on port other than 21, your router doesn't do that.
enable PASV mode on your port 20 site.