[R] Error Message: MCMCpack and coda

[rbest1@binghamton.edu]

Hello All,

I'm trying to run a one-dimenional irt model using the packages MCMC and
coda on a rather large set of roll-call voting data with many missing
observations.  Here's a sample of the code:
Post10<-
MCMCirt1d (Italy10, burnin = 1000, mcmc=50000, thin=100, verbose=TRUE,
theta.constraints = list(V549=1, V443=-1))

The MCMCirt1d command seems to work fine, but when I try to summarize the
output I get the following error message(s):

summary(Post10)
Error: NA/NaN/Inf in foreign function call (arg 1)
In addition: Warning message:
Step size truncated due to divergence

My understanding is that this has something to do with the missing data,
though I don't know how to address this issue.  Any help would be greatly
appreciated.

Thank you,
Robin Best