Cuando ingreso a mi foro creado en webcindario, me sale una pagina en blanco(www.euromanager.webcindario.com) y me han dicho que debo ir ha http://www.euromanager.webcindario.com/install.php pero me sal esto:

A critical error has occurred.

This installer was unable to find the installer's language file or files. They should be found under:

In some cases, FTP clients do not properly upload files with this many folders. Please double check to make sure you have uploaded all the files in the distribution.

If that doesn't help, please make sure this install.php file is in the same place as the Themes folder.

If you continue to get this error message, feel free to look to us for support.

lo que dice es que no encontró el archivo de idioma , que debe estar en /Themes/default/languages asegurate que lo has subido correctamente en esa ruta.