Math font problem under Mac OS X Lion

[Luca Brandolini]

I am running LyX under Mac OS X 10.7.5.  In the math edit mode the mathematical 
symbols are not displayed correctly. For example instead of an integral I get 
an accented "o".
I tried  running LyX debug mode (-dbg mathed) and in the log I found lines of 
the kind
     "font cmm not available and I can't fake it"

I tried to reinstall LyX but I had the same behavior.

Luca Brandolini