Bernhart,

Error "XML schema too compex" means you can't use xmladapter. Period.
In short, you need to use your own routine that would get data from xml file, and piece by piece, and put data into prepared cursors.
You should know in advance how many cursors you need, and how they relate to each other.

What method you use to read xml file and to extract information from there, it depends on your preferences and experience. Among methods are msxml.domdocument and Excel Automation, to name a few. For instance you can open xml file in Excel, and in one worksheet you will get field headers and data.

Hope you understand the idea.

Good Luck