I can not save my Schema as a DTD file using Tamino Schema Editor.
Do anybody know a tool to get the DTD of a Tamino Schema ?

A product called “Turbo XML” which come from http://www.extensibility.com can handle Tamino schema. “Turbo XML” is a schema editor that allows you to perform interchange between different schema standard. For examples, DTD → XSD; Tamino schema → DTD etc.

Hello Mehmet,
some caveats apply here:
Note that the Tamino 2.x schema format as stored in Tamino is not directly recognized by Turbo XML. The new schema format introduced with Tamino 3.1, however, is a strict XML Schema subset, and therefore covered by most third-party tools.
Also, when converting from any schema format into DTDs (whichever tool you use) will probably result in information loss, as schema dialects are more expressive than DTDs.
Finally, depending on what you need the DTD for, a perfectly viable way to obtain it may be to generate it from one or more sufficiently typical instance documents. Tools like Turbo XML support this approach.