hgimportsvn: command not found

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

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

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/hgimportsvn - from package: hgsvn

You may install the required package with command apt-get install {package}

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