rcapid: 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/rcapid - from package: isdn4k-utils

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

On Debian possible default full paths are:

/usr/sbin/rcapid - from package: capiutils

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

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