How can I find the content that I see in "view source"?

I work on a website that uses besides the backend also a frontend editor to add content. When I now try to work on the side in this “activate editor” I get the 500 error. But only on my start page. Everything else (the website itself, the dashboard and the activate editor on all other subpages works perfectly). So it has to be something I added recently on that page. I think I already figured out what it is: I ebedded a google maps link on the home page. So I really want to delete it. But I did it with the editor in the frontend that is no longer available. In the backend I cannot change it, it doen′t even exist. I checked all php files and the stylesheet but it does not come up. When I go online to “view source” I get a HTML site where I find it directly. So where do I find this in my ftp Files or in the Dashboard? Or can I changed it somehow in the view source file?

I need really your help, it takes me now more than five hours only searching in all files in my ftp server and also in the dashboard editor I have looked more than twice to every single php file…. Thank you very much!