You have coded figure1_CloseRequestFcn in a way that calls upon a function that you expect to be in the MATLAB path, but turns out not to be because you relied upon it being in the current directory instead of creating a specific MATLAB path entry for the appropriate directory.
What you can do, is in the OpenFcn for the GUI, use mfilename() to detect where the .m file for the GUI itself is located. fileparts() to get the directory, and cd to that directory, recording the old directory. Now take the handle of the function that you need in the close request function, and store it in handles; then cd back to the old directory.
Then in the close request function, pull the handle of the function out of the handles structure, and use it to call the needed function, instead of counting on the function being in the current directory. When you construct a handle of a function using @ then MATLAB remembers the directory the code is located in and so knows where to find it.