I dont know why this is happening, but every time I try to use /list, my client crashes. I have no idea if this is client side or not, but i figured I would post it anyway and see if anyone else had this issue. (/list was working yesterday )
Crashes every time for me. I'd recomend a full-reinstall of mincraft, (its folder is hidden in your user area under .application folder) Only thing I can think of, havn't tried it though yet.
An easy way toreinstall MC is by going into the .minecraft folder and deleting the "version" file. This makes MC think that it is running for the first time, so it reinstalls all of the MC client code.