difficulties with tuplets

[Die4Willes]

Hi there!

After solving the problems with lilypond's installation
it was working very fine until tuplets came up in a Sonata by
Brahms. According to the tutorial the command should be:

"\times 2/3 { d'8 fis' a' }"

but after invoking "ly2dvi -P Brahms.ly" it says:

"kpathsea: Running mktextfm cmti8
mktextfm not found
...
assertion 'source' failed..."

My questions are: where do I get this file from and in which 
directory do I have to put it?
I have been looking for it on miktex.org but didn't find it.
Who can help me??

Ciao for now
        Stefan