Until Windows 8.1, I had no problem using it. After the update, I wasn't able to connect anywhere. So I tried to desinstall and reinstall the software and now, I get the "The Smart FTP Client 64-bit setup does not work on your computer. Please download and run the 32-bit setup."
I have a 64 bits OS.
No problem, I'll try the 32 bits setup.
Now, i ger the "Use dedicated 64-bit setup on Windows 64-bit Editions".
Can you help me with this case?
Thank you!

It's a bug in Windows 8.1 that causes this problem. Right-click on the .exe, run as Administrator.

As simple as that! It's working perfectly again! Thank you for your support and quick answer!