serialver: 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/lib/jvm/java-1.5.0-gcj-4.8-amd64/bin/serialver - from package: gcj-4.8-jdk
/usr/lib/jvm/java-1.5.0-gcj-4.9-amd64/bin/serialver - from package: gcj-4.9-jdk
/usr/lib/debug/usr/lib/jvm/java-7-openjdk-amd64/bin/serialver - from package: openjdk-7-dbg
/usr/lib/jvm/java-7-openjdk-amd64/bin/serialver - from package: openjdk-7-jdk

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

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