After upating to the latest version of the RSForm! Pro - RSMail! integration plugin, the RSMail! form component is not working.
This is generated, because the latest version of the RSForm! Pro - RSMail! integration plugin creates a separate installation of the plugin. In order to solve this you will need to go to the Joomla! installer and uninstall the plugin System - RSForm! Pro - RSMail! Subscription(rsmail_rsformpro_subscription).
After this, the integration between the two components can be configured as explained here.