unionBugs: 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/unionBugs - from package: findbugs

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

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