Question
When I try an push to my remote repo (Unfuddle) using TortoiseGit, my favourite tool, I get the following error. I then open GitGUI and am able to push with no problem. I have gathered through some googling that pageant needs to be running for some PuTTY variants, and it is running. Where do I look next?

No supported authentication methods available (server sent: publickey)

Answer
I had the same problem.

I think the problem was that my Putty key was not set in my TortoiseGit Settings. I had to convert my bitbucket repository private key to a putty private key (.ppk file).

This is how I fixed it:

I downloaded puttygen.exe

I opened puttygen
I clicked Conversions -> Import key -> (imported my “~/.ssh/id_rsa” key)
I confirmed my key passphrase
I clicked “Save private key” and saved the key in my “~/.ssh/” folder
I went in my TortoiseGit settings : (right click on my master folder) -> TortoiseGit -> Settings -> Git -> Remote -> origin -> Putty key -> … -> (I added my newly generated putty private key)

And voilà, I was able to push to my origin repository.