VBA ActiveWorkbook.SaveAs not working

Hi to everyone

I have some troubles to solve/finish my macro and I need your help! What I want to do is the following:

• type in the path with the excel file
• in the excel create a new sheet with some text in it
• protect the new sheet
• protect the whole excel file
• save the file

The problem occurs at the last step and the file is not saved (the created sheet is protected). Can please someone explain where is the mistake?

I also noticed that the macro is running through all files in folder even though the files are not excel format. How to fix this as well?

In attachment you can find my file! Thanks for help!