Blender 2.49b not showing button when I run script on ubuntu like it does in windows?

[Vido]

I have an add-on for Blender 2.49b, python 2.6.2 and I need it to "show the button" to a user like this:

result=Blender.Draw.PupMenu("Sketchfab Viewer ?%t|Yes|No")

But button does not show up in ubuntu, but it does in windows?

To run script open blender2.49b and go inside addon folder and open Blender249.blend press Alt+P in text windows and go in to addon folder than go in to 768dd88bd0bb49a8ad0a75ab143f685a and select astrea-768dd88bd0bb49a8ad0a75ab143f685a.html and hit Import. Then you should see



but that button does not show up in ubuntu. I tried to debug addon by adding "2" on line 43 and it does not show up in console so I doubt that addon contain some windows only releted code like cls

Also one thing should be changed before you run addon on line 3277 change

os.system("cls") 

to

#os.system("cls")

And on picture below is shown some debuging

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I cant edit my post so I will put quick commands for downloading stuff here

1: Blender

wget https://download.blender.org/release/Blender2.49b/blender-2.49b-linux-glibc236-py26-x86_64.tar.bz2

2: Python

wget https://www.python.org/ftp/python/2.6.2/Python-2.6.2.tgz

Extract python and cd in to it and download this patch
3:Patch

wget https://bugs.python.org/file14045/python-2.6.2-svnversion.patch

and apply it

patch -p 0 < python-2.6.2-svnversion.patch

4. Compile python

./configure && make -j3

5. Setup Python

export PYTHONPATH=/home/username/Downloads/Python-2.6.2
export PYTHONPATH=/home/username/Downloads/Python-2.6.2/Lib

6. Run Blender

./Downloads/blender-2.49b-linux-glibc236-py26-x86_64/blender ~/Downloads/Blender249\[osgjs\]\[2017-02-23\]/Blender249.blend

7. Run script Alt + P and navigate in to addon folder than go in to 768dd88bd0bb49a8ad0a75ab143f685a and select astrea-768dd88bd0bb49a8ad0a75ab143f685a.html and hit Import, after that you should see buton Sketchfab Viewer but on my ubuntu machine it does not show up

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Edit2: Download Blendr add-on by clicking on link at beginning of my post

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Edit3:After I press Import script runs but it does not show any error just exits silently