japicompat: 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
/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/japicompat - from package: japitools

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