Error in eval(predvars, data, env) : object 'medv' not found

Please help I am getting this error;

Error in eval(predvars, data, env) : object 'medv' not found

My code

# LM
set.seed(7)
fit.lm <- train(medv~., data=dataset, method="lm", metric=metric, preProc=c("center",
"scale"), trControl=trainControl)

My data does have medv;

>print(DTset)
      CRIM   ZN INDUS CHAS    NOX    RM   AGE    DIS RAD TAX PTRATIO      B LSTAT MEDV  
2  0.02731  0.0  7.07    0 0.4690 6.421  78.9 4.9671   2 242    17.8 396.90  9.14 21.6
3  0.02729  0.0  7.07    0 0.4690 7.185  61.1 4.9671   2 242    17.8 392.83  4.03 34.7
4  0.03237  0.0  2.18    0 0.4580 6.998  45.8 6.0622   3 222    18.7 394.63  2.94 33.4