In workflow modeler you have two options to publish the workflow to Teamsite server.1. File--> Publish Workflow - This will copy and submit the .ipm & default_config.xml file to Teamsite sever.2. File --> Save to Server - This will only copy the .ipm & default_config.xml file in Teamsite sever.When you make changes in available_models.xml file it will look all the workflow models available in stagging area. If the .ipm file is not available in stagging area then the user will get this error.