require(R2jags)
Data <- list(x=x, n=length(x))
model <- function() {
  ## Likelihood
  for (i in 1:n) {
    x[i] ~ dnorm(mu, pow(sigma.sq, -1))
  }
  
  ## Prior
  mu ~ dnorm(0, 0.0001)
  sigma.sq ~ dunif(0, 1e7)
}
## Fixes problem:
## init <- list(list(mu=0, ssq=1))
fit <- jags(Data, param=c("mu","sigma.sq"), model=model, n.chains=1, n.iter=10000, n.burn=0, n.thin=1, DIC=FALSE)
attach.jags(fit)
dnplot(sigma.sq, xlab=expression(sigma^2))