If you go to http://files.minecraftforge.net/fmllibs/ you'll see a list of files. Find the ones you need and click to download them. Be aware that two of the files have been renamed to have .stash on the end, simply take the .stash off the filename once it's downloaded (you'll see a warning about changing file type, just click OK) - then put these files into the /lib directory in your server's root dir.
Worked for me, in any case.