serial problems

I've been exploring options for my final project and I settled on an idea featuring MIDI, Serial communication, and some sort of audio imput and spectral processing in Pure Data. Unfortunately, I've hit a roadblock on the very first step. For some reason, when I try to open up a serial port in Terminal, I get weird error messages. Here is what I've done so far. I opened up

/Applications/Processing\ 0133/libraries/serial/macosx_setup.command; exit

and then attempted to type in a new terminal shell the following:

screen/dev/tty.usbserial-5B1 9600

// but I get an error message that says this: No such file or directory


Any thoughts? I will try to solve this problem ASAP. In the meantime I'll start to post some sketches for a final project prototype.