This is not a question of you updating your version. I can see what you did, but not what you were hoping to do. Suppose I try this:
Error using load
Unable to read file 'randomstuff.mat'. No such file or directory.
So, if I try loading a file that does not exist, it gives me an error, telling me the file does not exist, but NOT what you got.
What did you get?
Unrecognized function or variable 'carsmall'.
Error in Exercise_3_1 (line 8)
That tells me the load did work, but there is no variable named carsmall in that .mat file.
I would suggest you try this:
Name Size Bytes Class Attributes
Acceleration 100x1 800 double
Cylinders 100x1 800 double
Displacement 100x1 800 double
Horsepower 100x1 800 double
MPG 100x1 800 double
Mfg 100x13 2600 char
Model 100x33 6600 char
Model_Year 100x1 800 double
Origin 100x7 1400 char
Weight 100x1 800 double
So there is indeed no variable by that name in the .mat file. Lots of other stuff, but not carsmall. What you want to do next is up to you.