Error mixing VB.Net & C#

The main program is Vb.Net and 3 projects are C#.  The VB project had a need for 2.0 version so I changed everything to 2.0.  But I get this error.  I do not know if I even should put this in this topic.  I do not know where to go with this.  I looked online a got no where.

Any help will be appreciated.
arep 

System.Configuration.ConfigurationErrorsException: An error occurred creating the configuration section handler for userSettings/InsuredLivesX.My.MySettings: Could not load file or assembly 'System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' or one of its dependencies. The system cannot find the file specified. (C:\MedAI\VB\InsuredLivesX\InsuredLivesX\bin\Debug\InsuredLivesX.vshost.exe.Config line 5) ---> System.IO.FileNotFoundException: Could not load file or assembly 'System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' or one of its dependencies. The system cannot find the file specified.

File name: 'System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'

   at System.Configuration.TypeUtil.GetTypeWithReflectionPermission(IInternalConfigHost host, String typeString, Boolean throwOnError)

   at System.Configuration.RuntimeConfigurationRecord.RuntimeConfigurationFactory.Init(RuntimeConfigurationRecord configRecord, FactoryRecord factoryRecord)

   at System.Configuration.RuntimeConfigurationRecord.RuntimeConfigurationFactory.InitWithRestrictedPermissions(RuntimeConfigurationRecord configRecord, FactoryRecord factoryRecord)

   at System.Configuration.RuntimeConfigurationRecord.RuntimeConfigurationFactory..ctor(RuntimeConfigurationRecord configRecord, FactoryRecord factoryRecord)

   at System.Configuration.RuntimeConfigurationRecord.CreateSectionFactory(FactoryRecord factoryRecord)

   at System.Configuration.BaseConfigurationRecord.FindAndEnsureFactoryRecord(String configKey, Boolean& isRootDeclaredHere)

 

=== Pre-bind state information ===

LOG: User = 1UPMC-ACCT\repaskya

LOG: DisplayName = System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089

 (Fully-specified)

LOG: Appbase = file:///C:/MedAI/VB/InsuredLivesX/InsuredLivesX/bin/Debug/

LOG: Initial PrivatePath = NULL

Calling assembly : System.Configuration, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a.

===

LOG: This bind starts in default load context.

LOG: Using application configuration file: C:\MedAI\VB\InsuredLivesX\InsuredLivesX\bin\Debug\InsuredLivesX.vshost.exe.Config

LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework\v2.0.50727\config\machine.config.

LOG: Post-policy reference: System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089

LOG: Attempting download of new URL file:///C:/MedAI/VB/InsuredLivesX/InsuredLivesX/bin/Debug/System.DLL.

LOG: Attempting download of new URL file:///C:/MedAI/VB/InsuredLivesX/InsuredLivesX/bin/Debug/System/System.DLL.

LOG: Attempting download of new URL file:///C:/MedAI/VB/InsuredLivesX/InsuredLivesX/bin/Debug/System.EXE.

LOG: Attempting download of new URL file:///C:/MedAI/VB/InsuredLivesX/InsuredLivesX/bin/Debug/System/System.EXE.

 

   --- End of inner exception stack trace ---

   at System.Configuration.BaseConfigurationRecord.FindAndEnsureFactoryRecord(String configKey, Boolean& isRootDeclaredHere)

   at System.Configuration.BaseConfigurationRecord.GetSectionRecursive(String configKey, Boolean getLkg, Boolean checkPermission, Boolean getRuntimeObject, Boolean requestIsHere, Object& result, Object& resultRuntimeObject)

   at System.Configuration.BaseConfigurationRecord.GetSection(String configKey, Boolean getLkg, Boolean checkPermission)

   at System.Configuration.BaseConfigurationRecord.GetSection(String configKey)

   at System.Configuration.ClientConfigurationSystem.System.Configuration.Internal.IInternalConfigSystem.GetSection(String sectionName)

   at System.Configuration.ConfigurationManager.GetSection(String sectionName)

   at System.Configuration.ClientSettingsStore.ReadSettings(String sectionName, Boolean isUserScoped)

   at System.Configuration.LocalFileSettingsProvider.GetPropertyValues(SettingsContext context, SettingsPropertyCollection properties)

   at System.Configuration.SettingsBase.GetPropertiesFromProvider(SettingsProvider provider)

   at System.Configuration.SettingsBase.GetPropertyValueByName(String propertyName)

   at System.Configuration.SettingsBase.get_Item(String propertyName)

   at System.Configuration.ApplicationSettingsBase.GetPropertyValue(String propertyName)

   at System.Configuration.ApplicationSettingsBase.get_Item(String propertyName)

   at InsuredLivesX.My.MySettings.get_dwOAO() in C:\MedAI\VB\InsuredLivesX\InsuredLivesX\My Project\Settings.Designer.vb:line 63

   at InsuredLivesX.SqlServConMgr.Open() in C:\MedAI\VB\InsuredLivesX\InsuredLivesX\SqlServCon.vb:line 6

   at InsuredLivesX.InsuredLives.extract.main() in C:\MedAI\VB\InsuredLivesX\InsuredLivesX\Extract.vb:line 25