[Imports] Problems uploading Burundi boundaries data

[Arie Scheffer]

Hello everybody,
I made my first large upload yesterday -Eurotime- and that went not very 
well. I now have a problem.
Before I started uploading I read up on the topic via the OSM wiki and 
thougth I had everything covered. I guess I was too optimistic. (T-T)
Let's start from the beginning...
(I describe my actions in detail, as it is my first time, you may be 
able to spot something I did wrong along the way)

I got my hands on a shp file of Burundi administrative borders 
(permission to use by FAO Africover).
I didn't want my first upload overly difficult so opted for JOSM to 
handle the upload, as I read JOSM would be fine if not attempting large 
uploads.
I decided creating an upload of national and provincial bounderies only 
this time around.
After simplifying and clean-up I was left with some 40,000 objects in 
the file, quite a reasonable size to my eyes.
I spent a few days creating new and editing existing relations for my 
boundaries, making sure relations / boundaries from neighbouring 
countries were not broken, then I validated the file and ironed out the 
errors found.

I noticed the pre-existing borders were not edited in many months, even 
years, and in the Burundi region is, as far as I could find out, only 
one active user -someone I stay in contact with- besides myself, so 
chances for someone starting to edit the boundaries just as I wanted to 
upload were slim. Just to be absolutely sure, I refreshed the osm-data 
file one last time, but no problems were found.
Then I started to upload. First time uploading JOSM froze up halfway. I 
restarted, refreshed the file, just in case there was data on the OSM 
server I needed to clean up. No problems there.
For my next try, I decided to upload in chunks of 1024 objects. 
Everything went smoothly. I checked whether my changeset was registered 
on the website and there it was, under # 8883488

This morning, on the online OSM map I couldn't find the changes I made . 
To check I downloaded a small part of Burundi into JOSM and found my 
edits missing. I then opened my original data file and upon refresh it 
reported 40,000 conflicts!

Could someone explain to me what went wrong? What should I do to get the 
data on the OSM server?
I'm now stuck with a data file with 40,000 conflicts that I need to 
solve one-by-one?!

Please, help. Thank you
Arie