UPDATE :

Ooops, nevermind what I've just wrote, emplode's acting up again. It uploaded +/- 40files at a good speed, but now has slowed down considerably.
To give an indication : it takes +/- 3mins for ONE 13Mb file.
It's still going, but I expect it to crap out on me any minute now. So I guess my problem isn't solved anyway.

Anybody else ever experienced this?

UPDATE :

As I've expected, the unit did crap out on me. It went through all the 'to upload' files (an took it's fair amount of time too - 3hrs to upload the contents of 6cd's, mp3 format that is - that's what? 420Mb?), but it failed with the same synch error in the end. The result is that some of the uploaded files got through, others didn't. There seems to be no pattern in the order of which the files either got through or were rejected.

I can't help but wonder if something didn't go wrong when I manually formatted the drive and added some directories when the builder.upgrade file failed halfway. Maybe I forgot something? (a drirectory, a partition that didn't get formatted?)

If nobody can provide me with a resolution, I guess I'll re-do the whole thing, but I'll put the 10gig as master and the 48gig as slave then. I'll use the procedure Bonzi suggested, avoiding the usage of the disk.builder image alltogether.

Could someone @empeg (or anyone else for that matter) PLEASE help me with this, 'cause it's driving me crazy!