Can't configure OpenBabel node in Knime

Hi All,

I was trying to using openbabel in knime for the first time yesterday. I dragged OpenBabel icon to the workbench, and right-click to configure it. A dialog box poped up entitled "Dialog cannot be opened", saying "The dialog cannot be opened for the following reason: Missing predecessor node". However, I double checked with Knime installment folder, there is a subfolder for Openbable installed. I can open OpenBable GUI from there. Would you mind help me figure out how to make the OpenBabel available in Knime in my case?