insert_brackets: 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/insert_brackets - from package: xviewg

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