Hii , this error you must see when uploading your blogger theme so,

How you can solve it?

What think you do when uploading theme you extract your theme in folder and direct click on your theme it redirect you in any browser and you direct copy full code and paste it in your blogger and click on save and it give you this error .

And what think I do when uploading my blogger theme

I just open my blogger and click on theme section and click on customize and open edit html. and open my folder and left click on my blogger theme.xml and click open with and open it with notepad. And open my blogger and just copy fill code from note pad and paste it in blogger. just click on save  now my theme is successfully updated and error is solve .

Thanks

One more thing need to do before uploading the theme first of all backup your theme to change theme of blogger safely .

How to get backup of blogger theme ?

Open your blogger and click on customize and click on backup it show pop up to download backup