Problem with SQLiteConnection in C# WPF

I am developing a C# WPF project with an embedded SQLite Database. I have used SQLite before without problems but for some reason when I call:

SQLiteConnection conn = new SqliteConnection("my connection string");

However, when this code executes it displays the error

XamlParserException was unhandled Cannot create instance of MainWindow.xaml defined in assembly 'MyProject', Version=1.0.0.0... Exception has been thrown by the target of an invocation. Error in markup file 'MainWindow.xaml' Line 1 position 9.

At this position is the following code in the XAML file

<Window xmlns:my="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Input.Toolkit"  x:Class="MySQLBackup.MainWindow"

I have set the project to be .Net Framework 3.5 so I do not understandw why I am getting this error and why it is saying it is an error in the XAML when it calls the SQLiteConnection in the class file.

Thanks for any help you can provide.

UPDATE As requested below is the stacktrace and inner exception

Inner Exception

System.Configuration.ConfigurationErrorsException: Unrecognized configuration section userSettings/Gui.Properties.Settings. (C:\Users\Chris\AppData\Local\Microsoft\MySQLBackup.vshost.exe_Url_5ar2cuyxbdeg3v0bx5aak4mgjx2jmsbn\1.0.0.0\user.config line 17) at System.Configuration.ConfigurationSchemaErrors.ThrowIfErrors(Boolean ignoreLocal) at System.Configuration.BaseConfigurationRecord.ThrowIfParseErrors(ConfigurationSchemaErrors schemaErrors) at System.Configuration.BaseConfigurationRecord.ThrowIfInitErrors() at System.Configuration.ClientConfigurationSystem.OnConfigRemoved(Object sender, InternalConfigEventArgs e)

Stacktrace

at System.Configuration.ClientConfigurationSystem.OnConfigRemoved(Object sender, InternalConfigEventArgs e) at System.Configuration.Internal.InternalConfigRoot.OnConfigRemoved(InternalConfigEventArgs e) at System.Configuration.Internal.InternalConfigRoot.RemoveConfigImpl(String configPath, BaseConfigurationRecord configRecord) 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(SettingsP开发者_运维技巧rovider 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 MySQLBackup.Properties.Settings.get_app_dbPassword() in c:\users\chris\documents\visual studio 2010\Projects\MySQLBackup\MySQLBackup\Properties\Settings.Designer.cs:line 43 at MySQLBackup.SqlDatabaseWork..ctor() in c:\users\chris\documents\visual studio

2010\Projects\MySQLBackup\MySQLBackup\Logic\SqlDatabaseWork.cs:line 25

I've managed to resolve it. I think it was something to do with the user.config file that is created by the application. I deleted the user.config and then told visual studio to rebuild and then it seemed to work.

Thanks for your help