I had a similar problem where i was creating a document workspace with office 2007 and the address i used was "http://localhost:7070/alfresco". Only my pc could update the document via share point. On everyone else pc it would fail to connect, hex editing the document showed that it was trying to connect to http://localhost:7070/alfresco which was wrong (for other pc's), so after an hour of searching the web and reading this post several time i resized that i was the one that had made the mistake. I removed the document workspace and recreated it with "http://my-externalip:7070/alfresco" and it worked from anywhere after that and adding the ip to my trusted sites. dont know if this had anything to do with what you were talking about but i thought i would post it anyway.
