Change your mode from active to passive... or is it the other way around... I never remember... Whatever the mode is now change it to the other.

One uses just port 21, the other uses port 21 for commands and port 22 for data. The information you want from the lst command, (which goes out on port 21), is being returned through the data channel, (port 22), which is being blocked by a firewall.... Set it so the mode uses only port 21 and all will be well with the world...