ps2lexmark: 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/ps2lexmark - from package: printer-driver-c2050

You may install the required package with command apt-get install {package}
Error in other languages:
ps2lexmark: bevel nie gevind nie
ps2lexmark: comandă negăsită
ps2lexmark: comando não encontrado
ps2lexmark: commande introuvable
ps2lexmark: command not found
ps2lexmark: käsku ei ole
ps2lexmark: không tìm thấy lệnh
ps2lexmark: komanda nerasta
ps2lexmark: Kommando nicht gefunden.
ps2lexmark: kommandot finns inte
ps2lexmark: komut yok
ps2lexmark: nie znaleziono polecenia
ps2lexmark: níor aimsíodh an t-ordú
ps2lexmark: no se encontró la orden
ps2lexmark: no s'ha trobat l'ordre
ps2lexmark: opdracht niet gevonden
ps2lexmark: parancs nem található
ps2lexmark: perintah tidak ditemukan
ps2lexmark: príkaz nenájdený
ps2lexmark: příkaz nenalezen
ps2lexmark: команда не найдена
ps2lexmark: командата не е открита
ps2lexmark: 命令找不到
ps2lexmark: コマンドが見つかりません