Cannot connect to my FTP

[Mumtaz]

I have a DS508 running firmare version 2.3.1157

Ever since I updated the firmware I am unable to connect to my FTP
Nothing has changed in my FTP settings from before the update

Is there some changes I need to make to these settings to get it to work after the update
Or, is this an inherent problem with FTP... if so, what must I do to make it work again

Also, do I need to change my router settings (I use Apple Airport Extreme)
Currently (and as before) my NAT forwarding points to port 21

Need help asap...

[Mumtaz]

My apologies... further to my earlier post (see below) I forgot to mention the error message I get when I try and connect to my FTP
The message I get is this:
Could not connect to server "xxx.xxxx.xxx"
Server closed connection

Many thanks in advance for your help
************
I have a DS508 running firmare version 2.3.1157

Ever since I updated the firmware I am unable to connect to my FTP
Nothing has changed in my FTP settings from before the update

Is there some changes I need to make to these settings to get it to work after the update
Or, is this an inherent problem with FTP... if so, what must I do to make it work again

Also, do I need to change my router settings (I use Apple Airport Extreme)
Currently (and as before) my NAT forwarding points to port 21

Need help asap...