Understanding "Cell contents reference from a non-cell array object." error

i try to convert table mnew to array. Below is my code. Please help me to understand. I also tried tabletoarray(has error too) n tabletocell not suitable to my needs.

for iii = 1 : k %k=4
   for jj = 1 : noofcol-1 %11-1
      val2 = mnew{iii,jj};
      if (ischar(val2))
         val2 = str2double(val2);
      end
      M_M(iii,jj) = val2;
   end
  end 
   MMM = reshape(M_M,k,noofcol-1)

however there is an error

"Cell contents reference from a non-cell array object.
    val2 = mnew{iii,jj};

[James Tursa]

Well, what does this show?

whos mnew

[Khairul Nur]

mnew is table 4x11

14 25 14 11 11 13 12 12 12 13 'DE0-29351'

13 24 14 10 11 14 12 13 12 14 'C1-121286'

14 25 15 11 11 14 12 12 10 14 'AG0-7CGUV'

13 25 14 11 12 14 12 12 13 13 'B0-21946'

[James Tursa]

So. the curly braces { } are for use with indexing into cell arrays, and mnew is not a cell array, hence the error.