qucsveri: 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 CentOS possible default full paths are:

/usr/bin/qucsveri - from package: qucs

You may install the required package with command yum install {package}

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