[MiKTeX] YAP does not load font

[Francisco A. S. G. <fg...@us...>]

I have an error message when YAP is executed and see File - Doucment 
Properties as suggested by the message and get (among other messages):

eorm10.pk >>>Not loadable - Double-click to see details.

When I double-click the message YAP says:

Making PK font:
C:\PROGRA~2\Miktex\miktex\bin\makepk.exe --verbose eorm10 657 600 
magstep(0.5) ljfour
Trying to make PK font "eorm10" (at 657 DPI)...
Creating "eorm10.pk"...
"mf" \mode:=ljfour; \mag:=magstep(0.5);nonstopmode;input eorm10
This is METAFONT, Version 2.71828 (MiKTeX 2.4)

(C:\Program Files\Miktex\fonts\source\public\ecc\eorm10.mf
(C:\Program Files\Miktex\fonts\source\jknappen\ec\exbase.mf
! This can't happen (copy).
mode_def->(EXPR5000)
                    :=incr.number_of_modes;mode_name[(EXPR5000)]:=str(EXPR50...
<to be read again>
                   =
l.1140 mode_def canonical_sharp_mode =
                                       % nearly |proof| mode
Transcript written on eorm10.log.
METAFONT failed for some reason
makepk: METAFONT failed on "eorm10".


DVIPS also coannot creat the ps file.

How can I create thes fonts?

Francisco Grossi