pbm2lex: 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/pbm2lex - from package: pbm2l7k

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

Error in other languages:
pbm2lex: bevel nie gevind nie
pbm2lex: comandă negăsită
pbm2lex: comando não encontrado
pbm2lex: commande introuvable
pbm2lex: command not found
pbm2lex: käsku ei ole
pbm2lex: không tìm thấy lệnh
pbm2lex: komanda nerasta
pbm2lex: Kommando nicht gefunden.
pbm2lex: kommandot finns inte
pbm2lex: komut yok
pbm2lex: nie znaleziono polecenia
pbm2lex: níor aimsíodh an t-ordú
pbm2lex: no se encontró la orden
pbm2lex: no s'ha trobat l'ordre
pbm2lex: opdracht niet gevonden
pbm2lex: parancs nem található
pbm2lex: perintah tidak ditemukan
pbm2lex: príkaz nenájdený
pbm2lex: příkaz nenalezen
pbm2lex: команда не найдена
pbm2lex: командата не е открита
pbm2lex: 命令找不到
pbm2lex: コマンドが見つかりません