Failed to execute script 'convert_model' due to unhandled exception

I seem to have issues while adding certain kinds of models. For example, I attempted to add this model but got an error:

https://huggingface.co/CompVis/stable-diffusion-v-1-4-original

```
Error Traceback (most recent call last):
File "convert_model.py", line 47, in
AssertionError
[81998] Failed to execute script 'convert_model' due to unhandled exception!
```

I have been able to successfully add other .ckpt models, so I'm not sure what's going on here.

Thanks!