date/time errors in certain .php files

[tpeck]

I am getting a lot of date/time errors in the domain log;

[Sun Apr 07 22:32:35 2013] [error] [client 173.199.114.243] PHP Warning: date() [<a href='function.date'>function.date</a>]: It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected 'America/Chicago' for 'CDT/-5.0/DST' instead in /home/aap/public_html/zencart/includes/languages/english/email_extras.php on line 30

They refer to entries like $date_range = time(); on the php pages.

Is there a one-stop solution somewhere - a checkbox or something - that fixes things?

[DrByte]

Is there a one-stop solution somewhere - a checkbox or something - that fixes things?

Yes.
It's in the log message you quoted:

You are *required* to use the date.timezone setting or the date_default_timezone_set() function.

Go to your server's php.ini and set date.timezone to a valid timezone.
If you don't have access to that file, get your hosting company to assist you or to show you how to set one up for your account specifically.