run-mozilla.sh: 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/xulrunner-devel-17.0.10/sdk/bin/run-mozilla.sh - from package: xulrunner-devel
/usr/lib/xulrunner-devel-17.0.10/sdk/bin/run-mozilla.sh - from package: xulrunner-devel

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

On Debian possible default full paths are:

/usr/lib/icedove-devel/sdk/bin/run-mozilla.sh - from package: icedove-dev
/usr/lib/iceweasel-devel-38/sdk/bin/run-mozilla.sh - from package: iceweasel-dev

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

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