[R] copula

[Dominique Katshunga]

Dear R-helpers,
is it some sort of R internal fault or am I doing something wrong when
typing the following two lines in R, I get the surface ploted and trying
it another time it gives the error message below:
> Error in ceiling(length.out) : Non-numeric argument to mathematical function
Why is it that sometimes I try the same commands and i get the copula
density plotted? I will appreciate any help.
thanks,
Dominique K.