CustomFieldRequiredValueNotProvided error!

I get this error when trying to create a new project to which i have added a new CustomField.

I have set all the values needed for the CustomField yet I am still getting this error...Here is my code:

projectCustomFieldsRow.CUSTOM_FIELD_UID = customField.FieldUid;
                        projectCustomFieldsRow.FIELD_TYPE_ENUM = (byte)PSLibrary.CustomField.Type.TEXT;
                        projectCustomFieldsRow.PROJ_UID = newCustomFieldValue.ItemGUID;
                        projectCustomFieldsRow.MD_PROP_UID = PSLibrary.CustomField.PROJECT_DEPARTMENT_MD_PROP_UID;
                        projectCustomFieldsRow.TEXT_VALUE = "test";

                        projectCustomFieldsRow.SetNUM_VALUENull();
                        projectCustomFieldsRow.SetFLAG_VALUENull();
                        projectCustomFieldsRow.SetDUR_VALUENull();
                        projectCustomFieldsRow.SetDUR_FMTNull();
                        projectCustomFieldsRow.SetDATE_VALUENull();
                        projectCustomFieldsRow.SetCODE_VALUENull();

                        projectDataset.ProjectCustomFields.AddProjectCustomFieldsRow(projectCustomFieldsRow);

When calling QueueCreateProject it throws an exception and the error message is the one stated above.

Any ideas why?