By default only files ending in .php, .php4 and sometimes .php5 are sent to the PHP processor. You can also have other file types sent there by adding a line or two to the htaccess file.
Been a while since I checked but I strongly suspect that none of the scripts on this site would require globals to be enabled. Even if globals were disabled but required it should return a PHP error message saying a variable does not exist.
That has nothing at all to do with using PHP in a HTML file. And on top of it having nothing to do with the topic at hand register_globals is disabled by default for a very good reason and only poorly written scripts would require it to be enabled.
Which translates as the number of hours you set it to multiplied by 3600 to get the number of seconds in that period. If you want to drop it to minutes just change the 3600 to 60.
That is assuming you are using the database version.
If using textfile version just open same file and replace both instances of 3600 with 60.
It will still be heavily encoded in the file you have. I had to run it through the decoding process about 10 times to get to the actual code. Talk about a stupid way of doing things.
I can easily put in a password that people are required to enter. I'll do it tomorrow. I've just been going through it tightening up security a little, fixing HTML tags and generally speeding it up by removing all the eval crap he had in there to hide the code used to check the copyright was in place and the spam checking function.