git-remote-hg: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/git-remote-hg - from package: git-remote-hg

You may install the required package with command apt-get install {package}
Error in other languages:
git-remote-hg: bevel nie gevind nie
git-remote-hg: comandă negăsită
git-remote-hg: comando não encontrado
git-remote-hg: commande introuvable
git-remote-hg: command not found
git-remote-hg: käsku ei ole
git-remote-hg: không tìm thấy lệnh
git-remote-hg: komanda nerasta
git-remote-hg: Kommando nicht gefunden.
git-remote-hg: kommandot finns inte
git-remote-hg: komut yok
git-remote-hg: nie znaleziono polecenia
git-remote-hg: níor aimsíodh an t-ordú
git-remote-hg: no se encontró la orden
git-remote-hg: no s'ha trobat l'ordre
git-remote-hg: opdracht niet gevonden
git-remote-hg: parancs nem található
git-remote-hg: perintah tidak ditemukan
git-remote-hg: príkaz nenájdený
git-remote-hg: příkaz nenalezen
git-remote-hg: команда не найдена
git-remote-hg: командата не е открита
git-remote-hg: 命令找不到
git-remote-hg: コマンドが見つかりません