dnsqr: 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

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 CentOS possible default full paths are:

/usr/bin/dnsqr - from package: ndjbdns

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