eric5_uipreviewer: 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 Debian possible default full paths are:

/usr/bin/eric5_uipreviewer - from package: eric

You may install the required package with command apt-get install {package}

Error in other languages:
eric5_uipreviewer: bevel nie gevind nie
eric5_uipreviewer: comandă negăsită
eric5_uipreviewer: comando não encontrado
eric5_uipreviewer: commande introuvable
eric5_uipreviewer: command not found
eric5_uipreviewer: käsku ei ole
eric5_uipreviewer: không tìm thấy lệnh
eric5_uipreviewer: komanda nerasta
eric5_uipreviewer: Kommando nicht gefunden.
eric5_uipreviewer: kommandot finns inte
eric5_uipreviewer: komut yok
eric5_uipreviewer: nie znaleziono polecenia
eric5_uipreviewer: níor aimsíodh an t-ordú
eric5_uipreviewer: no se encontró la orden
eric5_uipreviewer: no s'ha trobat l'ordre
eric5_uipreviewer: opdracht niet gevonden
eric5_uipreviewer: parancs nem található
eric5_uipreviewer: perintah tidak ditemukan
eric5_uipreviewer: príkaz nenájdený
eric5_uipreviewer: příkaz nenalezen
eric5_uipreviewer: команда не найдена
eric5_uipreviewer: командата не е открита
eric5_uipreviewer: 命令找不到
eric5_uipreviewer: コマンドが見つかりません