Hi,
Looks like you do not have FSUIPC (properly) installed. How to check: you should have a "fsuipc.dll" file in the "modules" subfolder of the main FS2004 folder.
Flight Logger needs this DLL to connect to the FS. Once you have it installed and the FS running, launch the Flight Logger and it should "see" the FS (and this will set the path, which is not to edit by hand).
Hope this helps
Andrei