gcj-dbtool: 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/gcj-dbtool - from package: libgcj

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

On Debian possible default full paths are:

/usr/bin/gcj-dbtool - from package: gcj-jre-headless
/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64/bin/gcj-dbtool - from package: gcj-4.8-jre-headless
/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64/jre/bin/gcj-dbtool - from package: gcj-4.8-jre-headless
/usr/lib/jvm/java-1.5.0-gcj-4.9-amd64/bin/gcj-dbtool - from package: gcj-4.9-jre-headless
/usr/lib/jvm/java-1.5.0-gcj-4.9-amd64/jre/bin/gcj-dbtool - from package: gcj-4.9-jre-headless

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

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