500 'SITE EXEC' not understood

Am attempting to unpack/run an ImageMagic-6.2.8-2-Q16-windows-dll.exe file through SmartFTP on my hosted server. I used the Custom Commands Serv-U (Execute File) option from the SmartFTP toolbar but received a 500 'SITE EXEC' not understood error message. Can I use SmartFTP to unpack/run this file? Or should I be attempting to do something differently? I set the CHMOD to 777 to be sure I could access the folder and file. From everything I read on the ImageMagic website, it tells me to upload the compressed file to my server and then run it from a browser window. I tried that, it didn't work, so I tried running it through SmartFTP and it still doesn't work. Any ideas or suggestions? I see a ton of "purchase a license" responses but I'm hoping to get a more informative response if possible. Thanks in advance for any help.

500 'SITE EXEC' not understood error message
This is a message from the server, the server does not support the "SITE EXEC" command. Changing the client won't improve this.