This is an error report.
Screenshot of the error

Error details
Hello, I'm on Unit 4 of the Blender course. I'm importing the different dae files (base, joint1 to 4) to blender, one by one. But only the base loads properly. I get the same error (attached on the screenshot) for joints 1 to 4. I've tried re-downloading the files in case it got corrupted but no change. I'm new to blender - is this somehting from my side or the files themselves?