Sounds like a structural issue. All those hrefs in the OPF file need to be relative to the OPF file in the epub's directory structure. And the file/folder names are case-sensitive. Make sure your folders are names 'html', 'css', images', etc. and not 'Html', 'Css' and 'Images'.
According to your OPF, your epub is constructed as follows (strictly from the perspective of the OPF file):
css/
cover.css
page1.css
page2.css
page3.css
html/
cover.html
page1.html
page2.html
page3.css
images/
cover.jpg
page1.jpg
page2.jpg
page3.jpg
fonts/
Booter_5-0.ttf
toc.ncx
content.opf
You really
should consider using an ePub validator before tossing one into Kindle Previewer.