If you are like me, you must hate it when your project in Eclipse shows up with annoying errors not relating to your source code. Such an error was turkey's urlrewrite dtd file.
The way I got rid of this error was to delete Eclipse's cache of the dtd file.
Simply go to Preferences>General>Network Connections >Cache.
Select the URL http://tuckey.org/res/dtds/urlrewrite3.0.dtd and click on Remove.
Save your urlrewrite.xml file and Eclipse would download and cache the file again.
The annoying error should be gone now!