Getting "Document is empty, line 1, column 1" on totally valid xml

[Alex]

Getting subj while parsing file (with [python libxml latest 3.3.0beta3, 3.3.0beta5) available on url: (an attached)
http://magazin.unipol.ru/service/unipol.xml

[2014-01-30 11:24:29,347] ERROR: Unhandled error during yml parsing Document is empty, line 1, column 1 Traceback (most recent call last):
  File "/home/user/frontend/digly/parsers/yml.py", line 672, in run
    self.parse_shop_feed(feed)
  File "/home/user/frontend/digly/parsers/yml.py", line 1015, in parse_shop_feed
    self.parse_data_huge() # this will be the method we use for any yml file
  File "/home/user/frontend/digly/parsers/yml.py", line 1335, in parse_data_huge
    for event, elem in ElementTree.iterparse(filepath or self.filepath, events):
  File "iterparse.pxi", line 179, in lxml.etree.iterparse.__next__ (src/lxml/lxml.etree.c:124387)
XMLSyntaxError: Document is empty, line 1, column 1

>>> print("%-20s: %s" % ('Python', sys.version_info))
Python : sys.version_info(major=2, minor=7, micro=3, releaselevel='final', serial=0)
>>> print("%-20s: %s" % ('lxml.etree', etree.LXML_VERSION))
lxml.etree : (3, 3, 0, -95)
>>> print("%-20s: %s" % ('libxml used', etree.LIBXML_VERSION))
libxml used : (2, 7, 8)
>>> print("%-20s: %s" % ('libxml compiled', etree.LIBXML_COMPILED_VERSION))
libxml compiled : (2, 7, 8)
>>> print("%-20s: %s" % ('libxslt used', etree.LIBXSLT_VERSION))
libxslt used : (1, 1, 26)
>>> print("%-20s: %s" % ('libxslt compiled', etree.LIBXSLT_COMPILED_VERSION))
libxslt compiled : (1, 1, 26)