Zhang Weiwu schrieb:
> Dear all
>
> I just emerged lyx and it doesn't work. The issue is class files are
> missing (one example is scrbook.cls). It should be installed together
> with lyx but it didn't.
>
> I need to install a package containing this file. to which package this
> file belongs to? I googled around without luck
>
> Thanks. The complete description of the issue is as follows:
>
> G. Milde's suggestion on solving my lyx problem:
>  
>> On 6.05.08, Zhang Weiwu wrote:
>>  
>>  
>>>> error message in opening tutorial with lyx. The opened tutorial is not
>>>> printable. see below:
>>>>      
>>>  
>>>    
>> ...
>>  
>>  
>>>> Warning: Document class not available
>>>> ----------------------------------------
>>>> The layout file requested by this document,
>>>> scrbook.layout,
>>>> is not usable. This is probably because a LaTeX
>>>> class or style file required by it is not
>>>> available.
>>>>      
>>>  
>>>    
>> ...
>>
>>  
>>  
>>>> zhangweiwu@(protected)
>>>> /usr/share/lyx/layouts/scrbook.layout
>>>>      
>>>  
>>>    
>> scrbook.layout is the LyX layout file, for printed output it requires the
>> *LaTeX class file* ``scrbook.cls``:
>>
>> milde@(protected)
>> /usr/share/texmf-texlive/tex/latex/koma-script/scrbook.cls
>>
>> Looking at Help>LaTeXConfig, you can find out which LaTeX classes and
>> packages are found by the latest Tools>Reconfigure run. Here I have:
>>
>>  Found: scrartcl: yes, scrreprt: yes, scrbook: yes
>>
>> Fix:
>>  
>> Find out which Gentoo package provides the file scrbook.cls and install
>> it (or install all classes that are marked as required, recommended or
>> suggested by LyX).
>>  
>
>  
www.portagefilelist.de could answer these kinds of questions.

But the package you are looking for is
dev-texlive/texlive-latexrecommended-2007.