I get the error below when trying to install Forum 5.0.2 on DNN 5.6.7. The portal was upgraded from 5.6.2 with no errors. I have tried removing the Forum tables, sp, desktopmodule files but still get the error. Any idea how to fis this?

SQL Execution resulted in following Exceptions: System.Data.SqlClient.SqlException: Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression. at System.Data.SqlClient.SqlConnection. (SqlException exception, Boolean breakConnection) at System.Data.SqlClient.SqlInternalConnection. (SqlException exception, Boolean breakConnection) at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj) at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj) at System.Data.SqlClient.SqlCommand.RunExecuteNonQueryTds(String methodName, Boolean async) at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(DbAsyncResult result, String methodName, Boolean sendToPipe) at System.Data.SqlClient.SqlCommand.ExecuteNonQuery() at DotNetNuke.Data.SqlDataProvider.ExecuteADOScript(String SQL) at DotNetNuke.Data.SqlDataProvider.ExecuteScript(String Script, Boolean UseTransactions) DECLARE @default_constraint_name SYSNAME, @sql NVARCHAR(3750)IF EXISTS ( SELECT name FROM dbo.sysobjects WHERE parent_obj = OBJECT_ID(N'dbo.Forum_EmailQueue_TaskEmails') AND type = 'D' AND id = ( SELECT cdefault FROM syscolumns WHERE name = N'DateAdded' ) ) BEGIN SELECT @default_constraint_name = name FROM dbo.sysobjects WHERE parent_obj = OBJECT_ID(N'dbo.Forum_EmailQueue_TaskEmails') AND type = 'D' AND id = ( SELECT cdefault FROM syscolumns WHERE name = N'DateAdded' ) SET @sql = N'ALTER TABLE dbo.Forum_EmailQueue_TaskEmails DROP Constraint ' + @default_constraint_name EXEC sp_executesql @sql END System.Data.SqlClient.SqlException: Column already has a DEFAULT bound to it. Could not create constraint. See previous errors. at System.Data.SqlClient.SqlConnection. (SqlException exception, Boolean breakConnection) at System.Data.SqlClient.SqlInternalConnection. (SqlException exception, Boolean breakConnection) at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj) at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj) at System.Data.SqlClient.SqlCommand.RunExecuteNonQueryTds(String methodName, Boolean async) at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(DbAsyncResult result, String methodName, Boolean sendToPipe) at System.Data.SqlClient.SqlCommand.ExecuteNonQuery() at DotNetNuke.Data.SqlDataProvider.ExecuteADOScript(String SQL) at DotNetNuke.Data.SqlDataProvider.ExecuteScript(String Script, Boolean UseTransactions) ALTER TABLE dbo.Forum_EmailQueue_TaskEmails ADD CONSTRAINT DF_Forum_EmailQueue_TaskEmails_DateAdded DEFAULT (GETDATE()) FOR DateAdded