dmenu.xft: 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/dmenu.xft - from package: suckless-tools

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