Excel Import ID, Data Type Double
The ID should definitely be an NVARCHAR and not a double, you can change the type it thinks it is in the mappings. Depending on your data validation settings it may be truncating or nullifying your non-double IDs to fit them.

As for the date issue, I can't seem to get that particular style of date to fail an import. If there is more to that field than just the date portion it's possible the time portion is causing the problem.