are you running stock linuxice or have you upgraded since (to 9.10 or 10.04)?
at any rate, the egalax drivers are trash. I recall having to turn on/off the monitor when that happens to get touch back. really annoying!!
I found this today and wonder if it'd be a useful alternative to using the closed egalax driver:
you'll have to uninstall the egalax driver (sh ./setup.sh --uninstall i think). and un-blacklist usbtouchscreen if it's been blacklisted by the egalax driver.
let me know if this works! I'm planning on trying it when I get my new carpc up and going.