pandoc-citeproc: 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/pandoc-citeproc - from package: pandoc-citeproc

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