emacs fortran 90 model

[Seiichiro Tanizaki]

When I edit the fortran source code with the suffix .f90, the 
digit-argument command doesn't work for a certain character.  
Specifically, ESC n with "*" or "-" only repeat the character once, but 
not n times.  It works fine for other characters.  Would someone help me 
figuring out this? I use Emacs version 21.2.1 on linux.
Sincerely,
Seiichiro