emacs 23.1 font problem

[Gerhard]

Hi,

Since some time ago, I am having problems with emacs loading 
.tex files. When I try to open such a file, I receive the 
following message, and font-lock is turned off:

File mode specification error: (error "Invalid face height" 
0.0)
File local-variables error: (error "Invalid face height" 0.0)

I can start auctex by M-x latex-mode, and then, font-locking 
is enabled. Apart from flyspell (where I have to change the 
dictionary by hand), everything seems to work normally 
afterwards, so it is only it little nuisance. 

When I start emacs with "emacs -q", and try to open a .tex 
file, I get the following:

File mode specification error: (error "Invalid face height" 
tex-suscript-height)

As before, I can start the (generic latex-mode) by M-x latex-
mode.

I have noted that in auctex as well, subscripts are displayed 
now in normal font, which was at some time different.

I am using a self-compiled emacs under Mandriva linux:

GNU Emacs 23.1.90.1 (x86_64-unknown-linux-gnu, GTK+ Version 
2.18.3) of 2010-01-08 on localhost

The emacs provided by Mandriva (also a 23.1) showed the same 
problem. I have seen that similar bugs have been reported, 
but I have not seen any response to it. 

Does someone of you have any idea what is going on here?

Thanks in advance,

Gerhard