bison++.yacc: 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/bison++.yacc - from package: bison++

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

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