Blogger or blogspotta What is and what is the y Content is not allowed in prolog. ”Error? You usually get this error when installing the theme.

Theme Download menu:

Blogger >> Template >> Backup to Restore. The reason for this error is that you try to load the theme as .zip or .rar as archived.

Error Solution:

If you upload your theme as an archive, ie. Zip or not .xml file, the problem is solved and your new theme is loaded.