shptreetst: 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/bin/shptreetst - from package: mapserver

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

On Debian possible default full paths are:

/usr/bin/shptreetst - from package: mapserver-bin

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

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