sosreport: 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/sbin/sosreport - from package: sos

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

On Debian possible default full paths are:

/usr/bin/sosreport - from package: sosreport

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

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