library('gamlss')
library('foreach')
library('doParallel')

registerDoParallel(cores = 4)
# Generate data
set.seed(314)
sample.size <- 30
input.processed.cut <- data.frame(TP = round(runif(sample.size) * 100),
                                  FP = round(runif(sample.size) * 100),
                                  x = runif(sample.size))
# Fit Beta-binomial
model3 <- gamlss(formula = cbind(TP, FP) ~ x,
                 family = BB,
                 data = input.processed.cut)

# Get the leave-one-out values
loo_predict.mu <- function(model.obj, input.data) {
  yhat <- foreach(i = 1 : nrow(input.data), .packages="gamlss", .combine = rbind) %dopar% {
    updated.model.obj <- update(model.obj, data = input.data[-i, ])
    predict(updated.model.obj, what = "mu", newdata = input.data[i,], type = "response")
  }
  return(data.frame(result = yhat[, 1], row.names = NULL))
}

par.run <- loo_predict.mu(model3, input.processed.cut)
# Error in { : task 1 failed - "object 'input.data' not found"

> version
               _
platform       x86_64-w64-mingw32
arch           x86_64
os             mingw32
system         x86_64, mingw32
status
major          3
minor          4.3
year           2017
month          11
day            30
svn rev        73796
language       R
version.string R version 3.4.3 (2017-11-30)
nickname       Kite-Eating Tree