Sorry, I now can't reproduce it. I made a tiny test script and it worked
fine on both Windows and Linux. Now when I run the real test that works
fine too. So could you close/remove this "bug" for me please?

#!/usr/bin/env python3
import sys
import urllib.request
print(sys.version)
fh = urllib.request.urlopen("http://www.python.org/index.html")
data = fh.read()
fh.close()
print(type(data))

# output when run on Linux:
3.0rc1 (r30rc1:66499, Sep 18 2008, 17:45:22)
[GCC 4.2.3 (Ubuntu 4.2.3-2ubuntu7)]
<class 'bytes'>

# output when run on Windows:
3.0rc1 (r30rc1:66507, Sep 18 2008, 14:47:08) [MSC v.1500 32 bit (Intel)]
<class 'bytes'>