c-icap-client: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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 Debian possible default full paths are:

/usr/bin/c-icap-client - from package: c-icap

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