The problem you are not defining the function used in fplot as an expresion with an specific variable. You also are trying to use 'e' as the 'exp()' function.
Try something like this:
fplot( @(x) -exp(-x + x.^2 - 2*x + 2), [0, 1]);
Maybe the function is not correct but you only have to change it according to your needs.
Hope this can help you. Bye.