[pymvpa] it is Not gizpped file

[cfygj]

Hi all,
When I conduct some MVPA, some error information emerged. Would you tell me how to address this problem. The attachment is my mask used in PyMVPA scripts.
Loading dataset...
using label file: /media/caifei/GSP1RMCULFR/attributes/bijiao/s1/attributes.txt
Traceback (most recent call last):
  File "mvpa_classifier.py", line 33, in <module>
    ds = fmri_dataset(samples=FMRIFile, targets=attrs.targets, chunks=attrs.chunks, mask = ('/media/caifei/GSP1RMCULFR/s1/standard2diff_mask5.nii.gz'))
  File "/usr/lib/python2.7/dist-packages/mvpa2/datasets/mri.py", line 235, in fmri_dataset
    maskimg = _load_anyimg(mask)
  File "/usr/lib/python2.7/dist-packages/mvpa2/datasets/mri.py", line 364, in _load_anyimg
    data = _img2data(src)
  File "/usr/lib/python2.7/dist-packages/mvpa2/datasets/mri.py", line 60, in _img2data
    img = nibabel.load(src)
  File "/usr/lib/pymodules/python2.7/nibabel/loadsave.py", line 54, in load
    return klass.from_filename(filename)
  File "/usr/lib/pymodules/python2.7/nibabel/spatialimages.py", line 411, in from_filename
    return klass.from_file_map(file_map)
  File "/usr/lib/pymodules/python2.7/nibabel/analyze.py", line 870, in from_file_map
    header = klass.header_class.from_fileobj(hdrf)
  File "/usr/lib/pymodules/python2.7/nibabel/nifti1.py", line 568, in from_fileobj
    raw_str = fileobj.read(klass.template_dtype.itemsize)
  File "/usr/lib/python2.7/gzip.py", line 261, in read
    self._read(readsize)
  File "/usr/lib/python2.7/gzip.py", line 296, in _read
    self._read_gzip_header()
  File "/usr/lib/python2.7/gzip.py", line 190, in _read_gzip_header
    raise IOError, 'Not a gzipped file'
IOError: Not a gzipped file
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.alioth.debian.org/pipermail/pkg-exppsy-pymvpa/attachments/20140820/f9ec920b/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: standard2diff_mask5.nii.gz
Type: application/x-gzip
Size: 1943 bytes
Desc: not available
URL: <http://lists.alioth.debian.org/pipermail/pkg-exppsy-pymvpa/attachments/20140820/f9ec920b/attachment-0001.bin>