Results 4 issues of Rocky Duan

Right now when the dimensions don't match, we see an AssertionError with no error messages. This should be made more informative as I can imagine it being a common error

bug

## 📌 Checklist before creating the PR - [ ] I have created an issue for this PR for traceability - [ ] The title follows the standard format: `[doc/gemini/tensor/...]:...

**Describe the bug** If the training data does not live on NFS but on node-specific storage, the current logic in https://github.com/NVIDIA/Megatron-LM/blob/0bc3547702464501feefeb5523b7a17e591b21fa/megatron/core/datasets/gpt_dataset.py#L346 skips building the indices and result in an error...

Is there any plan to support capsule as one of the primitive geoms? So that there's better feature parity with Mujoco. Also right now, loading URDF with capsule geom gives...

enhancement
P1