XML 04.03.04 covers these issues:
XML-5464 Search is now independent from the current HttpContext - works now also using Scheduler
A job called by scheduler doesn’t run in any HttpContext so an "Object reference not set to an instance of an object." was raised.
Side note: A lot of DotNetNuke objects and ASP.Net functions rely on HttpContext: e.g. objects like PortalSettings or mappath are not available during a scheduled task!
XML-5486 Change in util.vb to address assembly resolving issue
Some DotNetNuke installations were not able to resolve Net.Permissions to System.Net.Permissions causing a site wide exception. I want to apologize for this, even if the fix was simple
XML-5295 URL DataSource does not handle Username/Password correctly - fixed
XML-5364 XslCompiledTransform class Disallows XSLT extensions scripting...
...and keeps being disabled (more..)
DNN-5690 is not really an Xml issue:
Some other user reported a strange issue during installation of the module causing a NullReferenceException: Object reference not set to an instance of an object. at DotNetNuke.Common.Utilities.Config.AddCodeSubDirectory(String name)
This could happen to any 4.x WSP module; it is caused by an unnecessary default namespace inside web.config. DotNetNuke 4.5.2 is going to address that issue, in the mean time you can help yourself on removing xmlns="http://schemas.microsoft.com/.NetConfiguration/v2.0" from the web.config's configuration root node .