pm-uninstall: 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/pm-uninstall - from package: pmuninstall

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

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