Ans. ive noticed that the reason for this error can be one of the following:

1. if you look at the tile that this tile extends, and what that tile extends, until you find the tile that extends nothing, that tile should have a definition like this:
..some stuff..
the key thing, is that the path of the parent tile starts with a "/" character

2. if #1 is not your problem, then you might have a duplicate definition of the tile name which the error talks about.

3. Another thing that can happen is that your tiles path that you are referencing in struts-config.xml does not exist at all, because maybe you misspelled it, in which case that same error is thrown.

Posted on Dec 15, 2010 by Arindam