modelicac: 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/modelicac - from package: scilab-full-bin

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

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