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