Here's another error in epubveri.
Here is the code in the OPF.
Code:
<package xmlns="http://www.idpf.org/2007/opf" unique-identifier="e9780759525795" version="2.0" xml:lang="en-US">
epubveri reports no error. epubcheck reports: package.opf Line:2 Col:113 ERROR(RSC-005): Error while parsing file: attribute "xml:lang" not allowed here; expected attribute "id"
Changing an ePub3 to ePub2 without changing the rest of the code is actually pretty good at finding errors in epubveri.