This happened to me too, after installling the beta version of SDGSystems' fbvncserver beta version for the SL-6000. I have experienced the problem and found the touchscreen (/dev/sharp_ts, I guess) working again after uninstalling and rebooting.
I never got the pointer stuff working on it, either
[The instructions to run /etc/rc.d/inittab/fbvncinput did not work and I came out only with the error "/dev/sharp_ts: invalid argument". I haven't yet searched the enough of the forum threads for any workarounds, but I did look at the script. Please let me know if there is a quick and dirty solution that I might employ to get past this on the SL-6000.]
Honestly, the absence of coherent, timely support for this device is making me think that my time might be better spent helping to develop a more portable Linux distribution for other ARM processor devices, like the Hitachi G1000 I forsook for the Zaurus. I've gotten some great help from SDGSystems in a somewhat elective-type connection with the CF-2031 software, but that, too is annoying when you consider how incomplete Sharp has allowed the distributed software to remain.
I love linux; I like some of the features of the Zaurus, but as a device, it's not so unique as to warrant spending so much time dealing with Sharp's handling of the TrollTech QTDesktop syncing software on top of the apparent lack of collaboration with the developers working to make these applications work properly.
Anyway, I'm not bailing but needed to vent a little.