[R] random effects plot

[A Das]

Hi, does anyone know how to do random effects plots
for multi-level models? 
"plot(ranef(model))" doesn't seem to work in the
latest release. Here's the error message:
Error in table(x) : argument "x" is missing, with no
default
In addition: Warning message:
The 'formula' argument has been renamed to 'x'. See
?xyplot in: dotplot(formula = .groups ~ .pars |
.enames, data = list(.pars = c(-0.0388163041843026,  

Help a poor sociologist out... 
                          -Bobby