Errors in Loading Matlab Toolbox

Hi! I've a problem in loading .m files from plugins folder. I've pasted a toolbox in the directory: Macintosh HD/Applications/MATLAB_R2014b/toolbox and some plugins in the directory: Macintosh HD/Applications/MATLAB_R2014b/toolbox/nametoolbox/plugins

Currently, I'm using as Folder: /Users/xxx/Documents/Matlab.

Sometimes, when I try to use the functions provided by the toolbox or the plugins, it shows me the error: Undefined function 'xxx' which I may solve only copying all the .m files in the Folder.

Can you help me please?