Which OS are you running?
In the meantime, please do the following:
1) Create a root test folder: c:\test
2) Within that root folder, create another folder named tmp, e.g., c:\test\tmp
3) Within that root folder, create a test filed named test.txt, e.g., c:\test\test.file
4) In the list.txt file where you have FF2CB installed, add these two lines and save it:
5) Run the FF2CB.exe file and press Ctrl+K (unless you've changed the hotkey).
6) Attempt to paste into another folder using the standard Ctrl+V hotkey.
If that doesn't work, close down FF2CB from the tray menu, try running it with administrator rights, and repeat the Ctrl+K/Ctrl+V steps. Let me know how it goes.