WinBugs编译出现multiple definition of mode mu

Question

model
  {
  for(i in 1:N) {
  r[i]~dnorm(mu,deta)
 deta~dgamma(beta,alpha)
mu~dgamma(theta,namda)
# mu<-a+b*x[i]
}
beta~dgamma(0.03,0.01)
alpha~dgamma(0.02,0.01)
theta~dgamma(0.01,0.01)
namda~dgamma(0.01,0.01)
#mu~dnorm(0,1000)

}

list(r=c(0.47,0.46,1.18,0.61,0.79,0.83,0.57,0.57,0.51,0.73,0.41,0.87,0.92,0.57,0.38,1.07),
         N=16)

list( theta=0,alpha=0,beta=0,namda=0.1)

求大神指点