I'm deprecating this vim plugin for sending text to a REPL via GNU Screen. I've now switched to tmux and the tslime.vim plugin: http://www.vim.org/scripts/script.php?script_id=3023

For those who are still interested in using GNU Screen, I recommend vicle, on which this plugin was based. Vicle appears to be under active development: http://www.vim.org/scripts/script.php?script_id=2551