Multiple errors in ePub from PDF
Hi, I'm trying to upload a book as an eBook. I have the PDF that was used for the print edition. I've converted the PDF to an ePub (via an online converter), in order to upload it to Lulu. However, when I upload the ePub file, I get an error: "Your EPUB contains errors that must be addressed before you can proceed". I've pasted the first 5 lines of the error details below - the majority of errors are "alt" tags for images.
My question is: is there any way around this; can I upload a different file (via a different conversion process, perhaps?), or would I need to add "alt" tags for all images? I'm not sure I can do the latter, if I'm honest. ;-)
Any help appreciated, thanks in advance.
ERROR: Publisher value is missing in content.opf
ERROR: Unable to locate a valid publication date. A date with the event attribute publication (opf:event=publication) is required in content.opf
ERROR: Unable to locate a valid creator. A creator with the author role (role=aut) and the file-as attribute is required in content.opf
ERROR: value of attribute "lang" is invalid; must be an RFC 3066 language identifier in index_split_000.html on line 2
ERROR: element "img" missing required attribute "alt" in index_split_000.html on line 13
...(last line repeated many times for different images)...