Error after installing new theme

[ButikSalam]

Hello

I recently purchased "MegaTrone Tools" template from Prestashop.com.
After installation and enabling the theme, I got this error:

 (1/1) ContextErrorException
Warning: Declaration of VcPostnord::l($string, $specific = false) should be compatible with ModuleCore::l($string, $specific = false, $locale = NULL)

in vcpostnord.php line 670
at ErrorHandler->handleError(2, 'Declaration of VcPostnord::l($string, $specific = false) should be compatible with ModuleCore::l($string, $specific = false, $locale = NULL)', '/usr/www/users/chillomm/modules/vcpostnord/vcpostnord.php', 670, array('module_name' => 'vcpostnord'))in Module.php line 1078
at include_once()in Module.php line 1078
at ModuleCore::coreLoadModule('vcpostnord')in Module.php line 1071
at ModuleCore::getInstanceByName('vcpostnord')in Hook.php line 837
at HookCore::exec('displayHeader')in FrontController.php line 552
at FrontControllerCore->initContent()in IndexController.php line 37
at IndexControllerCore->initContent()in Controller.php line 255
at ControllerCore->run()in Dispatcher.php line 428
at DispatcherCore->dispatch()in index.php line 28

https://imgur.com/a/hPhFOmz
 

This was caused by another Prestashop module, so I deleted it and now I'm getting these errors:

(1/1) ContextErrorException
Warning: Invalid argument supplied for foreach()

in ttcategoryslider.php line 457
at TtCategorySlider->getWidgetVariables('displayHome', array('cookie' => object(Cookie), 'cart' => object(Cart)))in ttcategoryslider.php line 417
at TtCategorySlider->renderWidget('displayHome', array('cookie' => object(Cookie), 'cart' => object(Cart)))in Hook.php line 929
at HookCore::coreRenderWidget(object(TtCategorySlider), 'displayHome', array('cookie' => object(Cookie), 'cart' => object(Cart)))in Hook.php line 881
at HookCore::exec('displayHome')in IndexController.php line 39
at IndexControllerCore->initContent()in Controller.php line 255
at ControllerCore->run()in Dispatcher.php line 428
at DispatcherCore->dispatch()in index.php line 28

https://imgur.com/a/iukZLJS

Is there any way of resolving the first error as I need that module to work with the new template?
If not, then how do I fix the other error? I have tried searching for a solution but with no luck.
Any help is greatly appreciated!

Kind Regards

Edited December 19, 2018 by ButikSalam
Added errors into code boxes (see edit history)

[ButikSalam]

I tried adding some categories to the "TT - Category Product Slider" module but now I'm getting this error:
https://imgur.com/a/R4SRr34

[Nishith Nesdiya]

Hi...

please ask themes support and tell make themes compatible with  your php version

Thanks

Edited December 20, 2018 by Nishith (see edit history)