First off I love DNN and it's working quite well for us www.premgrp.com. I has been running just fine for almost a year now and recently I upgraded to the latest version. For a long time we were using I believe 4.0.3 and I upgraded to 4.3.4, then 4.3.5 yesterday, and now 4.3.6 today. I do a lot of custom module coding and I have one tweak to the core (signin page). Ever since I upgraded to 4.3.x I am getting these error in my designer. I've seen people elude to this on the site in the past and I've even seen "official" faqs on this issue saying things like "rebuild your site", but I can't. What am I missing here? There's got to be something blatently obvious that I'm missing here.

Namespace or type specified in the Imports 'DotNetNuke.Security.Roles' doesn't contain any public member or cannot be found. Make sure the namespace or the type is defined and contains at least one public member. Make sure the imported element name doesn't use any aliases.
Namespace or type specified in the Imports 'DotNetNuke.Services.Log.EventLog' doesn't contain any public member or cannot be found. Make sure the namespace or the type is defined and contains at least one public member. Make sure the imported element name doesn't use any aliases.
Namespace or type specified in the Imports 'DotNetNuke.Services.Upgrade' doesn't contain any public member or cannot be found. Make sure the namespace or the type is defined and contains at least one public member. Make sure the imported element name doesn't use any aliases.
Name 'Config' is not declared.
Name 'Config' is not declared.
Name 'GetUpgradeStatus' is not declared.
'UpgradeStatus' is not a member of 'Microsoft.VisualBasic.Globals'.
'UpgradeStatus' is not a member of 'Microsoft.VisualBasic.Globals'.
'UpgradeStatus' is not a member of 'Microsoft.VisualBasic.Globals'.
Type 'EventLogController' is not defined.
Type 'LogInfo' is not defined.
'Log' is not a member of 'Services'.
Name 'LogException' is not declared.
Name 'LoggingProvider' is not declared.
Type 'Services.FileSystem.FolderController' is not defined.
Type 'PortalController' is not defined.
Type 'PortalInfo' is not defined.
Name 'Scheduling' is not declared.
Type 'EventLogController' is not defined.
Type 'LogInfo' is not defined.
'Log' is not a member of 'Services'.
'Scheduling' is not a member of 'Services'.
Name 'Scheduling' is not declared.
Type 'Scheduling.SchedulingProvider' is not defined.
Name 'Scheduling' is not declared.
Name 'Scheduling' is not declared.
Name 'ServerName' is not declared.
Name 'ApplicationPath' is not declared.
Name 'ApplicationPath' is not declared.
Name 'ApplicationMapPath' is not declared.
Name 'ApplicationMapPath' is not declared.
Name 'ApplicationMapPath' is not declared.
Name 'HostPath' is not declared.
Name 'ApplicationPath' is not declared.
Name 'HostMapPath' is not declared.
Name 'HostPath' is not declared.
Name 'AssemblyPath' is not declared.
Name 'ApplicationMapPath' is not declared.
Type 'EventQueue.EventQueueController' is not defined.
'Scheduling' is not a member of 'Services'.
Name 'Scheduling' is not declared.
'Scheduling' is not a member of 'Services'.
Type 'Scheduling.SchedulingProvider' is not defined.
'Scheduling' is not a member of 'Services'.
Name 'LogException' is not declared.
Namespace or type specified in the project-level Imports 'DotNetNuke.Entities.Tabs' doesn't contain any public member or cannot be found. Make sure the namespace or the type is defined and contains at least one public member. Make sure the imported element name doesn't use any aliases.
Namespace or type specified in the project-level Imports 'DotNetNuke.Services.Exceptions' doesn't contain any public member or cannot be found. Make sure the namespace or the type is defined and contains at least one public member. Make sure the imported element name doesn't use any aliases.
Namespace or type specified in the project-level Imports 'DotNetNuke.Common.Utilities' doesn't contain any public member or cannot be found. Make sure the namespace or the type is defined and contains at least one public member. Make sure the imported element name doesn't use any aliases.
Namespace or type specified in the project-level Imports 'DotNetNuke.Entities.Portals' doesn't contain any public member or cannot be found. Make sure the namespace or the type is defined and contains at least one public member. Make sure the imported element name doesn't use any aliases.
Namespace or type specified in the project-level Imports 'DotNetNuke.UI' doesn't contain any public member or cannot be found. Make sure the namespace or the type is defined and contains at least one public member. Make sure the imported element name doesn't use any aliases.
Namespace or type specified in the project-level Imports 'DotNetNuke.Services' doesn't contain any public member or cannot be found. Make sure the namespace or the type is defined and contains at least one public member. Make sure the imported element name doesn't use any aliases.
Namespace or type specified in the project-level Imports 'DotNetNuke.Security' doesn't contain any public member or cannot be found. Make sure the namespace or the type is defined and contains at least one public member. Make sure the imported element name doesn't use any aliases.
Namespace or type specified in the project-level Imports 'DotNetNuke.Modules' doesn't contain any public member or cannot be found. Make sure the namespace or the type is defined and contains at least one public member. Make sure the imported element name doesn't use any aliases.
Namespace or type specified in the project-level Imports 'DotNetNuke.Framework' doesn't contain any public member or cannot be found. Make sure the namespace or the type is defined and contains at least one public member. Make sure the imported element name doesn't use any aliases.
Namespace or type specified in the project-level Imports 'DotNetNuke.Data' doesn't contain any public member or cannot be found. Make sure the namespace or the type is defined and contains at least one public member. Make sure the imported element name doesn't use any aliases.
Namespace or type specified in the project-level Imports 'DotNetNuke.Entities.Users' doesn't contain any public member or cannot be found. Make sure the namespace or the type is defined and contains at least one public member. Make sure the imported element name doesn't use any aliases.
Namespace or type specified in the project-level Imports 'DotNetNuke.Services.Localization' doesn't contain any public member or cannot be found. Make sure the namespace or the type is defined and contains at least one public member. Make sure the imported element name doesn't use any aliases.