the site is pretty buggy itself... i can just upload one thing, either the savefile or one Screenshot....Hi! Can you upload your save file and a screenshot of the 'not found' error to upload.taleworlds.com so that we can reproduce the issue faster.
You can find the save file here:
C:\Users\username\Documents\Mount and Blade II Bannerlord\Game Saves
Please include the link to this thread in the description box on the upload website so I can identify it.