csg_inverse: 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/csg_inverse - from package: votca-csg

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

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