When adding a item to your toolbox in Visual Studio from a network share, you may encounter one of the following errors:

• Insufficient state to deserialize the object.  More information is needed.
• The assembly '\\<assembly_path>' could not be loaded.  Check that any dependencies the file requires are installed.
• The file referenced by the shortcut file '\\<assembly_path>' cannot be opened.

The problem is security.  Here's the fix:

1. From the start menu, select [Control Panels] > [Administrative Tools] > [MS .NET Framework x.x Wizards]
2. Click [Adjust .NET Security]
3. Click [Next]
4. Select [Local Intranet] and make sure the slider below is at "Full Trust"
   
5. Click [Next]
6. Click [Finish]
7. Make sure you shutdown and restart Visual Studio before trying to add the items again.