tnameserv: 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/tnameserv - from package: gcj-4.8-jre-headless
/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64/jre/bin/tnameserv - from package: gcj-4.8-jre-headless
/usr/lib/jvm/java-1.5.0-gcj-4.9-amd64/bin/tnameserv - from package: gcj-4.9-jre-headless
/usr/lib/jvm/java-1.5.0-gcj-4.9-amd64/jre/bin/tnameserv - from package: gcj-4.9-jre-headless
/usr/lib/debug/usr/lib/jvm/java-7-openjdk-amd64/jre/bin/tnameserv - from package: openjdk-7-dbg
/usr/lib/jvm/java-7-openjdk-amd64/bin/tnameserv - from package: openjdk-7-jre-headless
/usr/lib/jvm/java-7-openjdk-amd64/jre/bin/tnameserv - from package: openjdk-7-jre-headless

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

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