Still getting the same error.
I copy/pasted the first example from
http://groovy.codehaus.org/Groovlets into ROOT/index.groovy. I added the web.xml lines to ROOT/WEB-INF/web.xml. I created the directory ROOT/WEB-INF/lib and copied the jar files from C:\Groovy\lib to it (groovy, antlr, and asm).
I did NOT make the context change to server.xml. I wonder if that is the problem. The ROOT webapp is implicitly defined I believe.
Here is part of the error I get:
java.lang.NoClassDefFoundError: javax/servlet/http/HttpServlet
G. Ralph Kuntz, MD