You've rather over-engineered things. The c.tld should not be extracted, and you don't need the web.xml declaration. The TLD should be automatically located in the JSTL jar file if you use the correct URI in the taglib directive.
Here's what I suggest:
1) Read the JSP FAQ to make sure that you are using compatible versions of JSP and the JSTL.
2) Be sure that both of the JSTL jar files are in WEB-INF/lib.
3) Remove the c.tld file from your hierarchy.
4) Remove the <taglib> element from your web.xml
5) Change the <% @taglib %> directive on your page(s) to reference the tld by its proper URI.
If that doesn't fix your problem, at least it gets a lot of dreck out of the way to find out what the real problem is.