Which version of ARGoS are you using?

In theory, the glitch you mention was solved in the latest version available in the download page.

Ok great. Tonight I'll make a new ARGoS distribution with this fix included.
Thanks a lot for spotting the bug!

No problem, here you go with the amd64 version.

Hi Nicola, I have prepared a test distribution of ARGoS for you. It contains a couple of fixes to the 2D dynamics physics engine that (in my tests) solve the problem that you mention. The distribution is for Ubuntu 10.04LTS and newer. With these fixes, the foot-bot is able to push/pull an object wei...

Thanks for spotting that! There was something weird going on with the Apache server. I changed the file name and now it should work as expected. Can you please confirm that?

http://iridia.ulb.ac.be/argos/upload/re ... 13.tar.bz2

I did and for me it works well. Also other people have downloaded it and uncompressed it with no problem.
What exactly is the error you get?