coplot and par

R 1.9.1 on Win2000 or Win98SE.

I am using coplot as follows:

coplot(AVG~LRPI| REGION)

the output seems normal but I get:

"Warning message:
calling par(new=) with no plot"

This is the only explanation that I have for being unable to use par() with 
coplot for changing the way the xlab and ylab appears. From within coplot I 
can change the text itself but not the font, fontsize, etc, but par() before 
coplot has absolutely no effect wahtsoever (maybe it isn't supposed to?).

I guess the question is: how can one change the way the xlab and ylab appear 
on a coplot?

Thanks,

Mihai
JSU