[SGML] impossible to use it in Emacs

[Hervaen]

Hi,

I like use sgml and try to install it on fedora, I have psgml, openjade, 
opensd, linuxdoc,

 but I don't have sgml-data, sgml-base, sgml-tools (I didn't found any package 
for fedora-core) 

In Emacs after typing <!doctype linuxdoc system> with shift and right button 
of the mouse I can have <linuxdoc></linuxdoc>

And that's all, after i have a bip with this message 

"External entity LINUXDOC not found"

I don't understand what is going wrong ??

Could you help me 

Hervaen