Hi @eddoff,
This issue [New sample file for Native Import/export · Issue #6265 · pkp/pkp-lib · GitHub] is posted and there is a PR, that it would help if you could check, regarding the sample XML file for import/export.
Regarding the fatal error above, it seems that your file has characters that can not be inserted or retrieved from the DB. (like ‘\xD1\x81\xD1\x82’). If you use other export methods, like Crossref export, and check the produced XML, do you get any wrong encodings?
Thanks