eiskaltdcpp-qt: 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/eiskaltdcpp-qt - from package: eiskaltdcpp-qt

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

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