My advice if you really need to support XP/IE8 is to download our extraskins.zip from our codeplex download page and try using one of the older skins. The newer skins we include and the ones on the demo site made with the latest Artisteer do not support those older browsers and the script for the skin may be causing errors that prevent the editor and other things from working. Older Artisteer 2.4 or 3.0 skins should support IE 8 though you may need to also enable the jquery migrate plugin as mentioned in the important skin changes if you use one of those older skins. I "think" the editors should work fine but other script errors will hose up the editor script. You could also try changing from CKeditor to TinyMCE to see if either one works better after changing to an older skin.
For best results use a newer OS and a modern web browser, but if you have no other choice then trying an older skin may help.