Can't listen on port 21

I just got this error, and now it won''t go away, and I can't communiceate with my Xbox. I have its IP down and I'm using the right cable for a network bridge. I figure this is a simple problem that you guys can solve. =)

* FlashFXP v[3].[2 ], build [1080], [ ]registered, [X]unregistered, [ ]pirated
* OS [X] WinXP, [ ] Win2K, [ ] Win98, [ ] WinME, [ ] Other
* Running behind NAT/router [ ] Yes & Model [ ], [X] No, [ ] Not sure
* Running firewall [ ] Yes, Name [ ], Ver. [ ], or [X] No
* Running Antivirus [X ] Yes, Name [Norton 2005] or [ ] No
* Network [X] xDSL, [ ] CABLE, [ ] Dail-Up, [ ] Other

additional info if related
* FTP server(s) name [Serve-U], version [?]
* WinSock 2.0 -- OpenSSL 0.9.7g 11 Apr 2005
Ident Server: Unable to listen on port 21