kmailservice: 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/kmailservice - from package: kdelibs3

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

On Debian possible default full paths are:

/usr/bin/kmailservice - from package: kdelibs-bin

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

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