1.5.2 error

[Francesco Menoncin]

Dear users,

I am on Ubuntu 7 and I have installed LyX 1.5.2. When I tried to view 
the DVI of a book I prepared with LyX 1.5.1, I get an error about the 
following command in the preamble:

\renewcommand{\thethm}{\thechapter.\arabic{thm}}

In particular it says that it does not understand "\thethm" for changing 
the theorem numbering.

Then I installed back LyX 1.5.1 and everything was compiled correctly.

I just wanted to remark this strange behaviour.

Thanks

Francesco