You have an XML file under (/system/bin/classes) that mentions a dtd file. On startup, CQ generates an error similar to the following:
21.09.2007 15:49:54 *ERROR* csd: Error while generating csdinfo (/system/bin/classes/abc/app/com/cache/manager/JmxCacheManager.xml): Page '/resources/dtd/mgt/model_mbean.dtd' does not exist.
These files have to reside within the JAR file or in a root folder in the contentbus /resources. Create a jar file with a "resources" folder in the jar and place your dtd files there. You can reference a dtd from an XML file as follows: cq:/resources/dtd/mgt/model_mbean.dtd.
For an example, see cq4.jar.