.MTS files ingest with no audio attached

I'm moving a pre-existing project to a new computer:

Intel Xeon Silver 4314

64GB of RAM

GeForce RTX Ti

Kingston 6TB HDDs

and when I opened it up, all the .MTS files from my Canon C100mkII could not be reconnected because:

"The selected file cannot be linked because its type (video) does not match the original file's type (audio and video)."

When I make a new project file and try ingesting any of my C100 footage, it all comes in as a video file with no audio even attached at all. This doesn't happen with any of the other assets in the premiere project (for instance, this is a documentary that uses a lot of assets from online, and those MP4s and MOVs don't have a problem ingesting).

What could be the problem here? Is it that the computer doesn't have the right codecs?