this problem is solved by giving preference R restore default or copying this path "C: \ Program Files \ KNIME_2.11.3 \ plugins \ org.knime.ext.r3.bin.win32.x86_3.0.3.0044664 \ R -inst " keep in mind that the path may vary according to the KNIME version you have.
Also try putting the local path of R from your computer, such as C: \ Program Files \ R \ R- 3.0.3
Bear in mind that the path may change according to the version of the R and the installation folder where you are.