seqxrefget: 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/seqxrefget - from package: emboss

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