Proper way to debug SVN+SSH checkout over VPN fail

In brief

Given a setup where SVN+SSH checkout over VPN is not working, and another where it is working, what is the correct procedure to find out what is the difference between two systems?

Details

I am using a 64-bit system running Windows 7. I have Open VPN and Tortoise SVN 64-bit installed.

The repository is in a remote system, and we connect using VPN.

Continuing from my earlier question SVN+SSH checkout over VPN using tortoise SVN, Smartsvn failing

One new teammate (working on exactly a system, 64-bit running windows 7, same as me) has successfully checked out from the remote server (connected via Open VPN). Both of us have followed the same steps -

Added some project specific Open VPN config files inside the config folder of the Open VPN installation path. Took these files from working setup of other team members.
Initiated Open VPN connection using a user.
ran Putty's Pageant.exe, selected the .ppk file and entered the pass phrase.

After his checkout was successful, I did a fresh installation of the softwares (OpenVPN, tortoiseSVN) using exactly the same ones he has used but still getting the following error when trying to checkout or using repository browser.

Error reads -

To better debug SSH connection problems, remove the -q option from 'ssh' in the [tunnels] section of your Subversion configuration file.
Network connection closed unexpectedly

But there is no such -q in the config file. Please read my prev question SVN+SSH checkout over VPN using tortoise SVN, Smartsvn failing to see what are the contents there.

I have verified that my windows firewall settings are exactly the same as his. But, there must be some difference between his system and mine. Here is a screenshot -

Note - He did not do any conversion of keys, just copied the contents inside Open VPN's config folder, like I did. I tried with the same files he used.

My question is what is the correct way to proceed from here?

Thanks