1. It's not a question to GIJ (he's not a xoops developer)
2. First search in forum (or just ask google)
3. go to this post
http://xoops.peak.ne.jp/md/d3forum/index.php?post_id=112174. If it doen't work see into /module.textsanitizer.php and look wchich function is called.
5. Which page gaves you that error?