tilecache_seed: 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
/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/sbin/tilecache_seed - from package: tilecache

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