Using dopar command with foreach in R

Recently I was trying to run an R code given by a programmer about parallel programming in R. The code is here. I used doParallel package ( doMC works too) to make a cluster and installed each necessary package like caret, e1071 etc to my newly installed last version 3.2.1 of R in Linux.
Sequential execution was working but when it comes to parallel execution I got an error like " Error in evaluation() : task 1 failed - "could not find function "knn3"" . I understood that that is because workers in parallel execution do not know about knn3 function.
After some research I found .packages option when calling foreach at vignettes of foreach package . Adding a vector list of necessary package names to foreach command's .packages options it worked.
Here is the working code:
 pr <- foreach(1:runs, .combine = rbind,.packages=c("caret","MASS","nnet","klaR","e1071","rpart")) %dopar% evaluation()