Ok, try this, uninstall FL, FLMM, and the CF mod, delete ALL the remaining folders and files that are left over from uninstall. When thats done, reinstall FL then restart your comp weather it says too or not. Then install the FLMM. After that download the CF 1.7 client, which can be found here: http://files.filefront.com/Cro…t/;8138097;/fileinfo.html (Is a clean and working copy) and install it. Once its installed activate it in the FLMM, then run the game and wait for it to patch itself, if it gives an E5 error, or any kind of error just close it and open it again, sooner or later it will fully update and let you onto the multiplayer. (If not then you have some sort of network problem)
If it still gives you problems after all that then something is seriously wrong with your PC because this has NEVER failed with me and my PC barely works enough to so much as open the start menu.