latex2png: 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/latex2png - from package: latex2rtf

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

On Debian possible default full paths are:

/usr/bin/latex2png - from package: latex2rtf

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

Error in other languages:
latex2png: bevel nie gevind nie
latex2png: comandă negăsită
latex2png: comando não encontrado
latex2png: commande introuvable
latex2png: command not found
latex2png: käsku ei ole
latex2png: không tìm thấy lệnh
latex2png: komanda nerasta
latex2png: Kommando nicht gefunden.
latex2png: kommandot finns inte
latex2png: komut yok
latex2png: nie znaleziono polecenia
latex2png: níor aimsíodh an t-ordú
latex2png: no se encontró la orden
latex2png: no s'ha trobat l'ordre
latex2png: opdracht niet gevonden
latex2png: parancs nem található
latex2png: perintah tidak ditemukan
latex2png: príkaz nenájdený
latex2png: příkaz nenalezen
latex2png: команда не найдена
latex2png: командата не е открита
latex2png: 命令找不到
latex2png: コマンドが見つかりません