I have some problems using dtifit of fsl.
 
Here are the lists of files
 20080811_204605ACEprotocol415086s007a1001.bval
 20080811_204605ACEprotocol415086s007a1001.bvec
 20080811_204605ACEprotocol415086s007a1001.nii.gz
 b0.nii.gz
 b0_brain.nii.gz
 b0_brain_eddy.ecclog
 b0_brain_eddy.nii.gz
 b0_brain_mask.nii.gz
 b0_eddy.ecclog
 b0_eddy.nii.gz
 
The 20080811_204605ACEprotocol415086s007a1001.nii.gz file had two volumes
and I extracted volume 0 using fslroi 20080811_204605ACEprotocol415086s007a1001.nii.gz b0.nii.gz 0 1
giving b0.nii.gz.
 
Then I extracted the skull using bet giving b0_brain.nii.gz and b0_brain_mask.nii.gz.
Then I used eddy_correct b0_brain.nii.gz b0_brain_eddy.nii.gz 0, giving b0_brain_eddy.ecclog, b0_brain_eddy.nii.gz
and eddy_correct b0.nii.gz b0_eddy.nii.gz 0, giving b0_eddy.ecclog, b0_eddy.nii.gz
 
However, when I try to use
dtifit -k b0_brain_eddy -o DTI -m b0_brain_mask -r 20080811_204605ACEprotocol415086s007a1001.bvec -b 20080811_204605ACEprotocol415086s007a1001.bval
"Error: data and bvals/bvecs do not contain the same number of entries" occurred

Typing in the following commands gave 
cat 20080811_204605ACEprotocol415086s007a1001.bval
0 1000
cat 20080811_204605ACEprotocol415086s007a1001.bvec
0 0
0 0
0 0
 
I think I have to modify the dimension of either bval or bvec, but I don't know how to.
Could anyone explain what the arrays of numbers in bval and bvec mean?
I don't know how I can figure out the number of entries in the b0_brain_eddy (data).
Thanks.