Indexed movie data values must be legal colormap indices:

hi,

I have a problem while using movie, in matlab. i am getting this error......

Indexed movie data values must be legal colormap indices:
1.0 <= value <= length(colormap) for double-precision movie data, and
0 <= value <= length(colormap)-1 for uint8 movie data

1. I am reading video file.
2. converting to rgb i am thresholding it.
3. while assigning the thresholded frame to mov(k).cdata=I; ( I is thresholded image)

I am getting abov error plz help me

Thanks in advance.