Here's a screen shot of 2 transactions that I created using an Excel-to-XML converter I built. Both uploaded without error. Some suggestions:
1) Don't use the Project ID as the Group ID. Create a non-intelligent sequential counter for the Group ID. Note that mine are 1000000 and 1000100 for the two transactions.
2) Populate External ID with some value. Again, the last part is a sequential counter (10000 and 10001). I use that same value for External ID and Voucher Number.
3) I don't think you need the Import Status value.
4) I use Unit = 1 and Actual Cost Rate = {the value} instead of the other way around.
Hope this helps! Good luck. -- Alan