asn2idx: command not found

Have You tried accessing the binary with the full path?

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/asn2idx - from package: ncbi-tools-bin

You may install the required package with command apt-get install {package}
Error in other languages:
asn2idx: bevel nie gevind nie
asn2idx: comandă negăsită
asn2idx: comando não encontrado
asn2idx: commande introuvable
asn2idx: command not found
asn2idx: käsku ei ole
asn2idx: không tìm thấy lệnh
asn2idx: komanda nerasta
asn2idx: Kommando nicht gefunden.
asn2idx: kommandot finns inte
asn2idx: komut yok
asn2idx: nie znaleziono polecenia
asn2idx: níor aimsíodh an t-ordú
asn2idx: no se encontró la orden
asn2idx: no s'ha trobat l'ordre
asn2idx: opdracht niet gevonden
asn2idx: parancs nem található
asn2idx: perintah tidak ditemukan
asn2idx: príkaz nenájdený
asn2idx: příkaz nenalezen
asn2idx: команда не найдена
asn2idx: командата не е открита
asn2idx: 命令找不到
asn2idx: コマンドが見つかりません