ill2fastq.pl: 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/ill2fastq.pl - from package: bfast

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

Error in other languages:
ill2fastq.pl: bevel nie gevind nie
ill2fastq.pl: comandă negăsită
ill2fastq.pl: comando não encontrado
ill2fastq.pl: commande introuvable
ill2fastq.pl: command not found
ill2fastq.pl: käsku ei ole
ill2fastq.pl: không tìm thấy lệnh
ill2fastq.pl: komanda nerasta
ill2fastq.pl: Kommando nicht gefunden.
ill2fastq.pl: kommandot finns inte
ill2fastq.pl: komut yok
ill2fastq.pl: nie znaleziono polecenia
ill2fastq.pl: níor aimsíodh an t-ordú
ill2fastq.pl: no se encontró la orden
ill2fastq.pl: no s'ha trobat l'ordre
ill2fastq.pl: opdracht niet gevonden
ill2fastq.pl: parancs nem található
ill2fastq.pl: perintah tidak ditemukan
ill2fastq.pl: príkaz nenájdený
ill2fastq.pl: příkaz nenalezen
ill2fastq.pl: команда не найдена
ill2fastq.pl: командата не е открита
ill2fastq.pl: 命令找不到
ill2fastq.pl: コマンドが見つかりません