albertje007
You have to update your template and modules to the lastest version. If you are coming from Joomla 2.5 to Joomla 3.9 there is a number of changes that you have to consider also. You need Joomlart T3 or T4 Framework installed and re-download all the free modules and plugins.
Start with the template and T4 or T3 Framework. And then modules and plugins.
Gavick Module and plugins may not work on Joomla 3.9 if you are coming from Joomla 2.5. And keep in mind the database change that happens when you jump from Joomla 2.5 to Joomla 3.9. So disable all your modules and plugins. Switch to Joomla default template and then start your joomla upgrade. Upgrade joomla first, to Joomla 3.9 and then replacing and changing your template, modules and plugins.
Don't make the mistake of trying to update a third party template and component, modules and plugins.
Joomla core CMS should be the first thing you upgrade. Joomla 2.5 to Joomla 3.9. Start by downloading the correct Joomla update. This will update your database so you don't lost data. Again, once you do that then start with the your template. Download a T4 or T3 Template and Framework and install. Once you get that working then plugins and modules.
Disable all the modules you have outline in your post. Once you get joomla updated, and install the correct T4 or T3 Framework then you can enable the modules and install the current version and it should fix th errors you are getting. But to install Joomla 2.5 Modules on Joomla 3.9 will generate the errors you are getting.
If you are a member of Joomlart you don't have to buy anything! just make sure you upgraded Joomla the right way!