[ BUILD # : 200710190000 ]
[ JDK VERSION : 1.6.0_02 ]

Create an incorrect XML file, e.g.

<?xml version="1.0" encoding="UTF-8"?>
<root>
    <module>
        <ext-connector>
            <inner><XY</inner>
        </ext-connector>
    </module>
</root>

Select Generate DTD... menu from the left-mouse button menu. The
following error message pops up:

Cannot proceed! The document contains syntax errors:
Element type "XY" must be followed by either attribute
specifications, ">" or "/>".

The corresponding dtd file is left over yet empty.

Note that the error message contains a typo - the comma after
"specifications".