lconvert: 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/lib64/qt5/bin/lconvert - from package: qt5-linguist
/usr/bin/lconvert - from package: qt-devel
/usr/lib64/qt4/bin/lconvert - from package: qt-devel
/usr/lib/qt4/bin/lconvert - from package: qt-devel

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

On Debian possible default full paths are:

/usr/bin/lconvert - from package: qtchooser
/usr/lib/x86_64-linux-gnu/qt4/bin/lconvert - from package: qt4-dev-tools
/usr/lib/x86_64-linux-gnu/qt5/bin/lconvert - from package: qttools5-dev-tools

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

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