xsun,
I just downloaded and double checked the Struts 1.1 release and there is no struts-validator.tld file… where is this file comming from?
Either way, just place it in the same location as your other TLD files, if you don’t have any other TLD files, then the most common place to put TLD files is under your WEB-INF directory, and be sure to add web.xml <taglib> entries for it and that the classes that implement the tags are in your Java Build Path.
Additionally if you have a lot of tag files or want to keep things organized, another common plaec is to put TLD files in a WEB-INF/tlds directory, make sure to update your web.xml <taglib> entries if you do.