Help getting value into an array

Question

Hi All Noobi here 

I'm having trouble getting a value into an array. When debugging PM1 will have a value 1-15 I can see that.
But when it hits 2nd line MM1 never gets a value, in the 3rd line theres still no value and  when i check dMain[0,1] it says 0.
If I change MM1 in the 3rd line to a number and check dMain[0,1] it has the same number!!!!!!
Where am I going wrong should this work? 
With both MM1 & MP1 I have declared them at form level and tried in the method but nether seem to work Ahhhh
Is there an easer way to do this as I had done similar in VB but have deleted some of the project.
Any help any help would be greatly appreciated.


  PM1 = randMain.Next(15);
  int MM1 = Numbers[PM1] ;
  dMain[0,1] = MM1;
  return;

I've now shrunk it down to:

                dMain[0,1] = Numbers[randMain.Next(15)];

But to no avail

Thanks in advance.
Mike.