Having problems when uploading a Sitecore Package from one environment to the next. Both environments have the same version level (Sitecore XP 8.1U3 / EXM 3.3).

Screen error message reads:

[NullReferenceException: Object reference not set to an instance of an object.]
   Sitecore.UIUtil.GetBrowserClassString() +347
   Sitecore.Shell.Controls.Standard.FormPageXmlControl.OnLoad(EventArgs e) +1154
   System.Web.UI.Control.LoadRecursive() +67
   System.Web.UI.Control.LoadRecursive() +164
   System.Web.UI.Control.LoadRecursive() +164
   System.Web.UI.Control.LoadRecursive() +164
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +4497

Sitecore Log Output:

3028 15:10:20 INFO  File has been uploaded: D:\inetpub\wwwroot\Sitecore\Data\packages\ColletteMailCoreSpeakApplication.zip
ManagedPoolThread #5 15:10:25 INFO  Job started: Install
ManagedPoolThread #5 15:10:25 INFO  Installing package: D:\inetpub\wwwroot\Sitecore\Data\packages\ColletteMailCoreSpeakApplication.zip
ManagedPoolThread #5 15:10:56 INFO  Installation was aborted at entry: items/core/sitecore/client/Applications/Collette Mail/{B1F6C86A-4F1D-4A60-8949-EC945ABE0675}/en/1/xml
ManagedPoolThread #5 15:10:56 INFO  Installation was aborted
ManagedPoolThread #5 15:10:56 INFO  Job ended: Install (units processed: )

Note that the Sitecore log does NOT show the 500 error displayed to the browser.

Process:

1. Upload Package File - Successful.
2. Click through to Name and License Dialog - Successful.
3. Clicking the Install button immediately throws error.

Package Contains:

Contains Sitecore items meant for the core database to install a new Speak Application.