This suggests that you have somehow added a builtin.m to your MATLAB path. You will need to track it down and remove it. If you are lucky then
which -all builtin
will show you the offending file.
You could experiment with using
restoredefaultpath; rehash toolboxecache
If that works then
savepath
You will likely need to do this for all versions of MATLAB.
But I suspect that you have builtin.m in your default MATLAB directory.