Symbolic package and Octave is working only for supersimple tasks. Am I doing anything wrong?

Question

I have installed (on Windows machine (Win7 64bit)):

• python 3.5.0 and sympy 0.7.6.1
• octave 4.0.0.0 and symbolic 2.2.2

This is what I get when I try to do anything with more than one operator:

>> pkg load symbolic
>> syms x
OctSymPy v2.2.2: this is free software without warranty, see source.
Initializing communication with SymPy using a popen2() pipe.
Detected Windows: using "winwrapy.bat" to workaround Octave bug #43036
Some output from the Python subprocess (pid 28092) might appear next.

OctSymPy: Communication established.  SymPy v0.7.6.1.
Python 3.5.0 (v3.5.0:374f501f4567, Sep 13 2015, 02:16:59) [MSC v.1900 32 bit (Int
el)]
>> x^2
ans = (sym)

   2
  x
>> x^2 + 2*x + 1
PYTHON: Error in var export
Resetting the octsympy communication mechanism
Closing the Python pipe...
error: python_cmd: unexpected return
error: called from
    python_cmd at line 143 column 6
    mtimes at line 42 column 5
>>

What is wrong?