vc1parser: 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/vc1parser - from package: mkvtoolnix

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

Error in other languages:
vc1parser: bevel nie gevind nie
vc1parser: comandă negăsită
vc1parser: comando não encontrado
vc1parser: commande introuvable
vc1parser: command not found
vc1parser: käsku ei ole
vc1parser: không tìm thấy lệnh
vc1parser: komanda nerasta
vc1parser: Kommando nicht gefunden.
vc1parser: kommandot finns inte
vc1parser: komut yok
vc1parser: nie znaleziono polecenia
vc1parser: níor aimsíodh an t-ordú
vc1parser: no se encontró la orden
vc1parser: no s'ha trobat l'ordre
vc1parser: opdracht niet gevonden
vc1parser: parancs nem található
vc1parser: perintah tidak ditemukan
vc1parser: príkaz nenájdený
vc1parser: příkaz nenalezen
vc1parser: команда не найдена
vc1parser: командата не е открита
vc1parser: 命令找不到
vc1parser: コマンドが見つかりません