There are a couple ways that you should be able to get around this. First you will need access to your php.ini on your server. If you do not have access to it on your server you should look into if they allow you to override their php.ini settings by making your own. If they do not, then you should probably look into finding a new host.
ini_set() has been disabled at the server level. You can either enable it and it will clean up all those warnings.
Or you can set display_errors in the php.ini to off. This should have the same effect.