I'm quite new to the matter of creating xml files from xls files. so below is proof of my 'Newbie-ship".

I have received an xml file (proper one, from government authorities, used multiple time by others, so I'm going with the assumption that the
cause for my issues in in the xls file with the source data I'm using.

I have all data, everything is mapped, but still get some error messages when I click the link in the xml-source panel 'Verify Map for Export ...'

It tells me that it's not exportable because :
1. List of lists
2. A mapped element's relationship with other elements cannot be preserved.

Now by googling and browsing this forum, I already found some suggestions, like making sure the data is contiguous.
To do that I made sure all the columns are in the very same order as in the xml map, every column has the correct format and deleted any column I do not need for the xml file.
(Is it allowed to have several tabs that the xml map maps to? There is some fixed (header) data that I placed in separate tab)

The list of lists I did not find a good explanation of root cause for, so also do not have a clue on solution.

Thanks in advance for your help.