dbsessmgr4: 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 Debian possible default full paths are:

/usr/bin/dbsessmgr4 - from package: mono-xsp4

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

Error in other languages:
dbsessmgr4: bevel nie gevind nie
dbsessmgr4: comandă negăsită
dbsessmgr4: comando não encontrado
dbsessmgr4: commande introuvable
dbsessmgr4: command not found
dbsessmgr4: käsku ei ole
dbsessmgr4: không tìm thấy lệnh
dbsessmgr4: komanda nerasta
dbsessmgr4: Kommando nicht gefunden.
dbsessmgr4: kommandot finns inte
dbsessmgr4: komut yok
dbsessmgr4: nie znaleziono polecenia
dbsessmgr4: níor aimsíodh an t-ordú
dbsessmgr4: no se encontró la orden
dbsessmgr4: no s'ha trobat l'ordre
dbsessmgr4: opdracht niet gevonden
dbsessmgr4: parancs nem található
dbsessmgr4: perintah tidak ditemukan
dbsessmgr4: príkaz nenájdený
dbsessmgr4: příkaz nenalezen
dbsessmgr4: команда не найдена
dbsessmgr4: командата не е открита
dbsessmgr4: 命令找不到
dbsessmgr4: コマンドが見つかりません