Cannot open image files with VMTK 4.1 PypePad

Operating system: Windows 10
Slicer version:
Expected behavior: Reading image files with no errors.
Actual behavior: I just installed VMTK 1.4 via Miniconda in a separate environment. Double clicking on a desktop shortcut opens PypePad. On an attempt to using its File|Open tabs to load .nii or .dcm files, error messages come up on the terminal window, like these ones:

Exception in Tkinter callback
Traceback (most recent call last):
File “C:\Users\Ja\miniconda3\envs\vm\lib\”, line 1558, in call
return self.func(*args)
File “C:\Users\Ja\miniconda3\envs\vm\lib\site-packages\vmtk\”, line 114, in OpenCommand
for line in openfile.readlines():
File “C:\Users\Ja\miniconda3\envs\vm\lib\encodings\”, line 23, in decode
return codecs.charmap_decode(input,self.errors,decoding_table)[0]
UnicodeDecodeError: ‘charmap’ codec can’t decode byte 0x90 in position 381: character maps to

I reinstalled VMTK few times, using Python 5, Python 6, and a binary Windows installer to no avail. The sys.getdefaultencoding() run on Python returns ‘utf8’.

Please help.