just learning pdg， some errors on the ROP mantra node don‘t work ， can you help me

Your scene is set up such that the File SOPs attempt to load `@pdg_output`. That variables resolves to the output of the active task -- if you want to render the input geometry file, you should instead set it to `@pdg_input`. Right now, when the Mantra work items render the File SOP is trying to load the output .exr file instead of the input geometry from the upstream work item.