Most standard FTP servers are not capable of downloading a file via the HTTP protocol.
If you were connecting to the server over SFTP and had shell access to wget you could do something like this directly from within FlashFXP
Main menu > Commands > Raw Command
Code:
/shell wget http://www.polyglot3000.com/download/poly3000.x32.exe
Then in the status window you'd see the result of the command
Code:
[10:59:26] [R] [CMD] wget http://www.polyglot3000.com/download/poly3000.x32.exe
[10:59:26] [R] [shell] Open
--2016-03-14 11:59:27-- http://www.polyglot3000.com/download/poly3000.x32.exewww.polyglot3000.com/download/poly3000.x32.exe
Resolving www.polyglot3000.com (www.polyglot3000.com)... 208.76.80.226
Connecting to www.polyglot3000.com (www.polyglot3000.com)|208.76.80.226|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 2782377 (2.7M) [application/octet-stream]
Saving to: 'poly3000.x32.exe'
2016-03-14 11:59:32 (566 KB/s) - 'poly3000.x32.exe' saved [2782377/2782377]
[10:59:31] [R] [shell] Close