[R] New user having problem with mcmc

[Lewis G Coggins]

I get the following error when I try to use mcmc.  It occurs at the end of
the first chain.

Error in cov(x.mon[2:m1, ] - x.mon[1:(m1 - 1), ]) :
        supply both x and y or a matrix-like x

Any ideas?

Thanks,

Lew