bibdoiadd: 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/bibdoiadd - from package: texlive-bibtex-extra

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