1. Disable internet connection, install FlashFXP.
2. Start application and register it with the key.
3. Disable automatic check for new version / updates:

Help --> Check for New Version --> Options --> (Uncheck) Remind me every --> Close

4. Stop FlashFXP from "calling home" with your firewall or/and add the following lines
in your hosts file (X:\Windows\system32\drivers\etc)...

127.0.0.1 flashfxp.com
127.0.0.1 flashfxp.org
127.0.0.1 flashfxp.ws
127.0.0.1 www.flashfxp.com
127.0.0.1 www.flashfxp.org
127.0.0.1 www.flashfxp.ws
127.0.0.1 liveupdate.inicom.net/verify.php
127.0.0.1 liveupdate.inicom.net
127.0.0.1 liveupdate.flashfxp.com
127.0.0.1 update.inicom.net
127.0.0.1 update.flashfxp.com

5. Edit FlashFXP.ini located in:
C:\Documents and Settings\All Users\Application Data\FlashFXP\3

And add/replace the lines

[LiveUpdate]
Last=40488
Proxy=0
Check=0
Address=
Port=80
user=
pass=
Interval=30
beta=0

6. Enable your internet connection.
7. Enjoy!