We are using Mercurial over SSH for our development. We use Hudson for continous integration, and have deployed it on Tomcat, running on a Windows 2003 Server using the Local System account. Mercurial is configured to use Putty's plink.exe as its ssh command in Mercurial.ini, together with a private key for SSH authentication.

When Hudson attempts any Mercurial command over SSH, the operation just blocks. I can see the three processes being started: hg.exe, cmd.exe and plink.exe. On the remote machine, I can also see the SSH session being opened and the authentication key being accepted.

After that, nothing appears to happen, and everything just blocks, seemingly forever. (As a side note, subversion/SVN over SSH works from Hudson to the same server, using the same user and authentication key).

A solution would of course be the best, but at least a hint for how I should debug it to get further would be nice, since I'm stuck and haven't even got an error message right now.