@UgurErcan I assume you are trying to use this workflow?
My suggestion would be to check your R installation with KNIME:
And then you might want to provide us with more details following the links in this article:
If you encounter a problem you also might want to ask a question in the KNIME Forum. To do that: read how to write a good forum entry or ask for help, then provide a sample workflow and maybe provide a detailed log file.