NAV 4.0 SP3 update 6 is available
Allthough I'm still waiting for the official announcement to know what has been changed and what has been solved, you can already submit a request to get the update.
It is all about Hotfix 940718 and you can obtain it through this link: http://support.microsoft.com/contactus2/emailcontact.aspx?scid=sw;en;1410&WS=hotfix .
It is filed under "limited release hotfixes" ... that's why you have to contact support. Customers can now submit their request online and the hotfix link will be emailed to them within 8 business hours, at least, that's what MS says. The only info you have to supply is the KB number (940718) and an email address.
As soon as I have more information about update 6 (The official KB article hasn't been published yet), I will put it on my Blog.