cross-ruby.rake: 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/lib/ruby/gems/1.8/gems/rake-compiler-0.9.3/tasks/bin/cross-ruby.rake - from package: rubygem-rake-compiler

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

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