'bspline_f' not found.
It does not appear that bspline_f is a part of MATLAB. That is, it is apparently not supplied by The MathWorks.
Did you write it? (Probably not, since Google finds at least one reference to it, by someone other than you.) In fact, I find exactly those lines of code written inside this .pdf file.
You probably found that same paper, and now want to run their code. Unfortunately, that link does not show the actual code for bspline_f as a function, nor do the references seem to be informative. So you might try contacting the author of that document (Eddie Nilsson).