Arrrg! I hate it! Driving me nuts! My computer started beeping with every mouse click in the Core FTP LE directory list menu. There was no error, no mention in the Options how to turn it off. Turns out...
it's a Windows bug! I'm using Windows Vista 64, and doing a search at Core FTP's forums brought me this page which took me to this Windows Knowledge Base article 944150. I choose the registry fix:
1. Click Start, type regedit in the Start Search box, and then click regedit in the Programs list. If you are prompted for an administrator password or for confirmation, type the password, or click Continue.
2. Locate the following registry subkey:
3. Right-click .Current, and then click Delete.
4. When you are prompted to delete this registry subkey, click Yes to delete the subkey.
5. Exit Registry Editor.
But I don't think it is permanent, I notice it started beeping again later. The other option is to replace your beep sound with dead air... yeah, right.