tixindex: 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/tixindex - from package: tix

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

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