v.surf.bspline: 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 CentOS possible default full paths are:

/usr/lib64/grass-6.4.4/bin/v.surf.bspline - from package: grass

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

On Debian possible default full paths are:

/usr/lib/grass64/bin/v.surf.bspline - from package: grass-core

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