C/C++ :: Invalid Operands To A Binary Expression

I've created a class that works with vectors doing various calculations and what not. I have overloaded operators that I've created outside of the main in separate header and class files. Ive tested them and the overloaded operators work correctly when I paste them into a the main file but when I have them defined in the other class files and I try to access them in the main class I get an error saying invalid operands to a binary expression. I also have other classes with overloaded operators that work just fine in the main class so I'm not sure what I did wrong here?

This is how I have my header set up, the definitions to these are in a separate class file which I don't think I need to include considering I have them tested and working so I don't think that's the problem (correct me if I'm wrong).

class VectorClass{
friend vector<float> operator+( const vector<float>&, const vector<float>& );
friend vector<float> operator...
friend vector<float> operator...
private:
...
...
public:
...

And then in my main class looks vaguely like this

#include "Name of vector class"
int main(){
vector<float> vR, v1, v2;
v1.push_back('some value');
...
v2.push_back('some value');
...
vR = v1 + v2; // Invalid operands here
return 0;
}

And like I said, I have other classes with overloaded operators set up the same way which work fine being implemented the way I have these, so I'm not sure where the problem is at.