To overcome the  below error, please follow the below steps:

This could be problem with the version of tm package installed. The above command will be work with tm package 5.1 Version.

Hence Remove the package:

Inline image 2

Downloading the tm package 5.1 version from the below URL:

Install the package with the below 

Command: install.packages("",repos=NULL) 

Please run the below command to check the version of tm installed.


and then run the DocumentTermMatrix and check.]