R help - Nov 2015 - Error in Contrast

Hey,
I was trying to implement Stochastic Gradient Boosting in R. Following is my
code in rstudio:

library(caret);
library(gbm);
library(plyr);
library(survival);
library(splines);
library(mlbench);
set.seed(35);
stack = read.csv("E:/Semester 3/BDA/PROJECT/Sample_SO.csv", head
=TRUE,sep=",");
dim(stack); #displaying dimensions of the dataset

#SPLITTING TRAINING AND TESTING SET
totraining <- createDataPartition(stack$ID, p = .6, list = FALSE);
training <- stack[ totraining,]
test <- stack[-totraining,]

#PARAMETER SETTING
t_control <- trainControl(method = "cv", number = 10);


# GLM
start <- proc.time();

glm = train(ID ~ ., data = training,
             method = "gbm",
             metric = "ROC",
             trControl = t_control,
             verbose = FALSE)

When I am compiling last line, I am getting following error:

Error in `contrasts<-`(`*tmp*`, value = contr.funs[1 + isOF[nn]]) : 
  contrasts can be applied only to factors with 2 or more levels


Can anyone tell me where I am going wrong and How to rectify it. It?ll be
greatful.

Thank you. Looking forward to it.

Regards,
Karteek Pradyumna Bulusu.

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