Sorry to hear...
Anyway, The msg box is indicating AC has failed to load a resource, why? because the resource isn't there!.. southdakota_circuit(.kn5) by name, as the above msg implies, is from the 1.0 release.
In release 1.1, the new KN5 track names are
-south_dakota_circuit_classic_gmrsc.kn5
- south_dakota_circuit_fia_extension.kn5
-south_dakota_circuit_full_enduro.kn5
Either the folder and files of the former 1.0 release are still present in the tracks folder or CM is caching the previous track somehow.
How it works:
In the 'Multiple Layout' scenario (for South Dakota release 1.1), AC uses the ini files in the track folder to point to which track layout is available. i.e.:
models_full_enduro.ini contains:
[MODEL_0]
FILE=south_dakota_circuit_full_enduro.kn5
POSITION=0,0,0
ROTATION=0,0,0
models_classic_gmrsc.ini contains:
[MODEL_0]
FILE=south_dakota_circuit_classic_gmrsc.kn5
POSITION=0,0,0
ROTATION=0,0,0
etc...
And the ui_track.json files for each layout only need a reference by name to display each track description i.e.:
{
"name": "South Dakota Circuit Full Enduro",
"description": "South Dakota Circuit",
...
and
{
"name": "South Dakota Circuit Full Enduro",
"description": "South Dakota Circuit",
...
etc...
In other words, this is the only purpose for the UI folder and ui_track.json files, so the models_xxxx.ini files are where its at if anything fails loading....
So definitely the above error is due to a call to a resource that isnt there and is not present in the southdakota_circuit (1.1).zip file... hence im suspicious theres some legacy stuff in your track folder somewhere that needs to be removed or CM Track Cache cleared.
I'm not too familar with CM's working underneath the hood unfortunately....so unless theres something else and I've lost the plot completely, try checking out the above and let me know if youre still getting errors.