Locally, using slime (the debian package) from the same machine, it works. But it fails (with the message "error in process filter: if: Wrong number of arguments: nil, 12") if I try to connect slime from a remote machine via a ssh tunnel (ssh -L 4005:127.0.0.1:4005 -p 2222 lispserveraddr; then M-x slime-connect).