bt2vrml: 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/bt2vrml - from package: octomap

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

On Debian possible default full paths are:

/usr/bin/bt2vrml - from package: octomap-tools

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

Error in other languages:
bt2vrml: bevel nie gevind nie
bt2vrml: comandă negăsită
bt2vrml: comando não encontrado
bt2vrml: commande introuvable
bt2vrml: command not found
bt2vrml: käsku ei ole
bt2vrml: không tìm thấy lệnh
bt2vrml: komanda nerasta
bt2vrml: Kommando nicht gefunden.
bt2vrml: kommandot finns inte
bt2vrml: komut yok
bt2vrml: nie znaleziono polecenia
bt2vrml: níor aimsíodh an t-ordú
bt2vrml: no se encontró la orden
bt2vrml: no s'ha trobat l'ordre
bt2vrml: opdracht niet gevonden
bt2vrml: parancs nem található
bt2vrml: perintah tidak ditemukan
bt2vrml: príkaz nenájdený
bt2vrml: příkaz nenalezen
bt2vrml: команда не найдена
bt2vrml: командата не е открита
bt2vrml: 命令找不到
bt2vrml: コマンドが見つかりません