wcalc: 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/wcalc - from package: wcalc

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

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