Socket binding to local port failed - FTP and SFTP Domains

[pje]

I have set up the Server with domains for FTP and SFTP

FTP is using port 21
SFTP is using port 22

I am using Server for Windows 9x on NT (NT version has dll problems)

The SFTP Domain starts up without error, but I get an error when the FTP Domain starts (but it seems to work ok on local LAN)

Starting Domain - XXXXXX [#1]...
XXXXXX active...
Starting Domain - YYYYYY [#2]...
The Socket binding to local port failed.
YYYYYY active...

Is this a serious error?
What needs to be done?

[pje]

Got it - all fixed.

Programs - Microsoft Internet Server - Internet Service manager.
There were three services running:
WWW
Gopher
FTP

I right-clicked and stopped all these.