We list 3000+ lines on Amazon, recently all most of our listings don't appear within Amazon Marketplace yet they show in our open listing within our account. Amazon say its a IT issue with them, has anybody else getting this problem.
I think that the way Amazon handle bulk uploads has been tweaked lately which may be why your programme is not functioning correctly. Probably just needs a tweak to your system to match but not being a bulk up-loader I wouldn't know what to do.
I think there's something on the # Amazon Seller Support Blog but you would probably do better to ask again on Seller Connection because more people read that.