nepomukfileindexer: 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/nepomukfileindexer - from package: nepomuk-core-runtime

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