Path does not start with a "/" character

Problem:
I get this error when using the tiles plugin when building out some tiles:

java.lang.IllegalArgumentException: Path .some.tiles.path does not start with a "/" character

first, lets pretend that the tile in question looks like this:
<definition name=".some.tiles.path" extends=".some.other.tiles.path"> ..some stuff.. </definition>

Solution:
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:
<definition name=".some.base.tile" path="/a/real/path/to/some/jsp/somejsp.jsp"> ..some stuff.. </definition>
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.