problems to create the index file ix01.html

Hi,

we have problems to create the index file ix01.html.

During the compilation of the docbook help files, we have an error message 
"HHC5003:Error: Compilation failed while compiling ix01.html. The index was 
created for the htmlhelp.chm correctly, but is not displayed in the 
separated html files.

There is another error message: HHC6003: Error: The file Itircl.dll has not 
been registered correctly. Microsoft HTML Help Compiler 4.74.8702.

We hope that you can help us. Thanks.

Regards.

G. Seemann