1.3.1: symbols in math

[Vaclav Smidl]

Hi,
I have just compiled 1.3.1 and it looks great but all symbols in mathed are 
replaced by TeX-names. I tried 
    lyx -dbg mathed
and got many of the following lines:
    font lyxsymbol not available and I can't fake it


However, everything was allright for 1.3.0. What has changed?
Is there an easy way around or should I go back to 1.3.0?

Thanks,

Vasek