Under Dynamic C installation C:\DCRABBIT_10.72\Samples\tcpip\ftp, there is FTP_CLIENT.C application, it is implemented by using the data handler functions.
It seems,Dynamic C has only the, ftp server side commands(APIs) to process the request that comes from the ftp client. Check more details in the ""Dynamic C TCP/IP Volume 2 User's manual".
To the best of my knowledge, you can implement the multi-thread software for both Web server and Ftp Client functionalities.
Also I suggest that, Download the
"Dynamic Web Pages With The Embedded Web Server" under "GEneral Documentation". it has sample webserver applications and some more information regarding the webserver implementation.You can find at the below location
I hope this helps you.