Error in IMFILL function

Hello , Am working in finding the area of circles in coins.png image.I have done watershed segmentation for this image and when am feeding the output image to find the area of each coin am getting a error in this line

C=imfill(B,'holes');

Program runs fine when i use the original coins.png image and it gives correct output ; am not getting output while using the watershed processed image.

The coding i use is below

I=imread('coins.png');
%Convert to Binary
B=im2bw(I);

%Fill the holes
C=imfill(B,'holes');

   %Label the image 
  [Label,Total]=bwlabel(C,8);
  %Object Number
  num=1;
  [row, col] = find(Label==num);

%To find Bounding Box
sx=min(col)-0.5;
sy=min(row)-0.5;
breadth=max(col)-min(col)+1;
len=max(row)-min(row)+1;
BBox=[sx sy breadth len];
display(BBox);
figure,imshow(I);
hold on;
x=zeros([1 5]);
y=zeros([1 5]);
x(:)=BBox(1);
y(:)=BBox(2);
x(2:3)=BBox(1)+BBox(3);
y(3:4)=BBox(2)+BBox(4);
plot(x,y);
%Find Area
Obj_area=numel(row);
display(Obj_area);
%Find Centroid
X=mean(col);
Y=mean(row);
Centroid=[X Y];
display(Centroid);
plot(X,Y,'ro','color','r');
hold off;

%Find Perimeter
BW=bwboundaries(Label==num);
c=cell2mat(BW(1));
Perimeter=0;
for i=1:size(c,1)-1
Perimeter=Perimeter+sqrt((c(i,1)-c(i+1,1)).^2+(c(i,2)-c(i+1,2)).^2);
end
display(Perimeter);

%Find Equivdiameter
EquivD=sqrt(4*(Obj_area)/pi);
display(EquivD);

%Find Roundness
Roundness=(4*Obj_area*pi)/Perimeter.^2;
display(Roundness);

Please let me know how to debug this

[Walter Roberson]

What is the error message you are encountering?