Varun has indicated to you that publishing to a network drive is NOT the way to go. You got away with it until this week, and now the gremlins have caught up with you. If you haven't changed versions or OS in Captivate recently then it's entirely possible something about the network has changed (e.g. under the hood there is some virtualisation going on).
Either way, experienced Captivate developers always publish LOCALLY and then later upload to the network if accessing the files from the network is required.