Grrr on you blogger!!!

I have been trying to change my template all day! I found four I really liked so I copied and pasted each code into the edit HTML box so I could preview them. They all worked great....so I finally decided on one, put the same code into the box, hit "save template", it asked if I definitely wanted to delete all widgets and things that were on my previous layout, I hit "confirm and save". However, NOW blogger won't let this layout post, and I keep getting an error message. So I tried different template from several different sites....same deal, except now it won't even let me preview the damn things. WTH is going on?!?!