OK, well it looks like you have a mismatch between what you think you have in your Excel columns and what the engine thinks you have.

This is sometimes caused, for instance, by trying to import an int column, and it having an empty cell in Excel. That will cause it to fall over.

You haven't said whether you're using the wizard to create a new table, or import into an existing one. To get it working, I suggest you "Create destination table" (you'll need to drop the existing one first). You'll find that under 'Edit Mappings'. For the Types, I strongly recommend you set them ALL to nvarchar and nullable, and make sure they're big enough to take the data. You can always CAST them later, or send them to a 'proper' SQL table with the correct data types, but the first thing is to get the data in.

Start with just one sheet. If that works, run it again adding the sheets one by one, and doing the same thin regarding the mapping.

That should get it working.