KOMA-Script Documentation Project

Hallo, kann mir irgendwer sagen was an diesem Minimalbeispiel falsch ist? Oder wo der Fehler herkommt.
scrartcl funktioniert in dieser form ohne Probleme. Hab schon ewig rumgesucht und finde nix dazu was dieser Fehler besagt. Vielleicht suche ich auch nach den falschen Stichworten.

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\documentclass{scrreprt}
\begin{document}
hallo
\end{document}

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$ pdflatex test.tex
This is pdfeTeX, Version 3.141592-1.30.6-2.2 (MiKTeX 2.5)
entering extended mode
(test.tex
LaTeX2e <2005/12/01>
Babel and hyphenation patterns for english, dumylang, nohyphenation, ge
rman, ngerman, french, loaded.
(scrreprt.cls
Document Class: scrreprt 2004/09/16 v2.9t LaTeX2e KOMA document class
("C:\Programme\MiKTeX 2.5\tex\latex\koma-script\scrlfile.sty"
Package scrlfile, 2006/03/28 v2.95 KOMA-Script package (loading files)
Copyright (C) Markus Kohm

) ("C:\Programme\MiKTeX 2.5\tex\latex\base\size11.clo")
("C:\Programme\MiKTeX 2.5\tex\latex\koma-script\typearea.sty"
Package typearea, 2006/07/30 v2.95b KOMA-Script package (type area)
Copyright (C) Frank Neukam, 1992-1994
Copyright (C) Markus Kohm, 1994-2002

("C:\Programme\MiKTeX 2.5\tex\latex\koma-script\scrkbase.sty"
("C:\Programme\MiKTeX 2.5\tex\latex\graphics\keyval.sty")

! LaTeX Error: Command \ifnumber already defined.
Or name \end... illegal, see p.192 of the manual.

See the LaTeX manual or LaTeX Companion for explanation.
Type H for immediate help.
...

l.178 }

?