Hello @lcollante ,
It maybe the link broken. Do your use git clone download the aml_npu_sdk? Use other method may cause link broken.
Second problem is the version of onnx opset. You can refer this topic.
Unable to convert yolov8n to .nb - VIM3 - Khadas Community
Is the problem still alive? It is the syntax error. Please check your command whether right or not.