There are several answers listed in Fixya under Z22 and touchpad or touch screen. You can start by trying to clean under the edges of the face frame with a credit card or something similar. If that doesn't work, try a soft reset by pushing the reset button on the back of the device. If that doesn't work, you can do a hard reset, but it loses all the data in the device. If you have it stored on your desktop calendar, this might solve the problem. To do a hard reset, check this site for instructions. http://kb.palm.com/wps/portal/kb/common/article/42094_en.html

If those steps don't work, you may need to replace the digitizer. You can pay someone to do it, or you can buy the part on ebay for about $12. Get one that comes with the tools you will need. Unfortunately, they don't come with instructions. I have posted the instructions in several places on Fixya. If you can't find them, write again. Hopefully the easier steps will do the trick.