Fatal Error: Call to undefined method InvalidArgum

Hello, I've just installed the Hot Clinic template on my server and when I try to access the backend I get this fatal error message:
Fatal error: Call to undefined method InvalidArgumentException::get() in /home1/xxxxxxxx/public_html/hotclinic/libraries/legacy/error/error.php on line 533
I contacted my server and they told me the server specifications are all ok. Also, the front-end shows without problem.
Any ideas what is causing this issue? Thanks.

Try to re-install maybe some file is not copied. Best is to unpack hot start zip directly on server that way you are sure all files are there.

Thank you, I'll try to unpack the zip file directly although I remember trying to do that before without success and then having to load it manually.