tilestache-server: 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/bin/tilestache-server - from package: tilestache

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