Here is the error message I see. Can someone decipher it and tell me how to fix it, please?

DotNetNuke.Services.Exceptions.ModuleLoadException: Instance failure. ---> System.InvalidOperationException: Instance failure. at System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, SqlConnection owningObject) at System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, Boolean ignoreSniOpenTimeout, Int64 timerExpire, SqlConnection owningObject) at System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(String host, String newPassword, Boolean redirectedUserInstance, SqlConnection owningObject, SqlConnectionString connectionOptions, Int64 timerStart) at System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(SqlConnection owningObject, SqlConnectionString connectionOptions, String newPassword, Boolean redirectedUserInstance) at System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, Object providerInfo, String newPassword, SqlConnection owningObject, Boolean redirectedUserInstance) at System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection) at System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnection owningConnection, DbConnectionPool pool, DbConnectionOptions options) at System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject) at System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject) at System.Data.ProviderBase.DbConnectionPool.GetConnection(DbConnection owningObject) at System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection) at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory) at System.Data.SqlClient.SqlConnection.Open() at Microsoft.ApplicationBlocks.Data.SqlHelperParameterCache.DiscoverSpParameterSet(SqlConnection connection, String spName, Boolean includeReturnValueParameter, Object[] parameterValues) at Microsoft.ApplicationBlocks.Data.SqlHelperParameterCache.GetSpParameterSetInternal(SqlConnection connection, String spName, Boolean includeReturnValueParameter) at Microsoft.ApplicationBlocks.Data.SqlHelperParameterCache.GetSpParameterSet(String connectionString, String spName, Boolean includeReturnValueParameter) at Microsoft.ApplicationBlocks.Data.SqlHelper.ExecuteReader(String connectionString, String spName, Object[] parameterValues) at DotNetNuke.Modules.FAQs.SqlDataProvider.SearchFAQList(Int32 ModuleId, Int32 OrderBy) at DotNetNuke.Modules.FAQs.FAQsController.SearchFAQList(Int32 ModuleId, Int32 OrderBy) at DotNetNuke.Modules.FAQs.FAQs.BindData() at DotNetNuke.Modules.FAQs.FAQs.Page_Load(Object sender, EventArgs e) --- End of inner exception stack trace ---

When I rolled it back the FAQ works fine it messes up when I try to upgrade the version of DNN

Maybe the faq is using a full text catalog? SearchFAQList ? What you can best do is download the source of faq, but the pdb files in your bin and connect with vs to checkout what is happening.