load() of a text file is only for files that are compatible with save -ASCII . Such files do permit comment lines with the usual % operator, but all other lines must be a rectangular array of numbers, the same number of numbers on every line. Such files represent a single 2D matrix.
What was your intention when you load() the .m file? Is it a script? If so then you use run() to invoke it, or just give its name. Is it a set of functions? If so then you can call upon the function whose name is the same as the name of the file, by giving that name.
If the .m file is a set of functions and you are trying to import all of the function definitions into your current code, then there is no way to do that, but sometimes people try something like that when they are looking for private functions
