package-stash-conflicts: 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 CentOS possible default full paths are:

/usr/bin/package-stash-conflicts - from package: perl-Package-Stash

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