topica2mail: 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 Debian possible default full paths are:

/usr/bin/topica2mail - from package: libwww-topica-perl

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

Error in other languages:
topica2mail: bevel nie gevind nie
topica2mail: comandă negăsită
topica2mail: comando não encontrado
topica2mail: commande introuvable
topica2mail: command not found
topica2mail: käsku ei ole
topica2mail: không tìm thấy lệnh
topica2mail: komanda nerasta
topica2mail: Kommando nicht gefunden.
topica2mail: kommandot finns inte
topica2mail: komut yok
topica2mail: nie znaleziono polecenia
topica2mail: níor aimsíodh an t-ordú
topica2mail: no se encontró la orden
topica2mail: no s'ha trobat l'ordre
topica2mail: opdracht niet gevonden
topica2mail: parancs nem található
topica2mail: perintah tidak ditemukan
topica2mail: príkaz nenájdený
topica2mail: příkaz nenalezen
topica2mail: команда не найдена
topica2mail: командата не е открита
topica2mail: 命令找不到
topica2mail: コマンドが見つかりません