PHP acting like HTML

Tried code that is working in another site (that I am abandoning). Fails, message not helping. Strange thing is when I use Firefox to look at generated code, I see is PHP code instead of PHP code. Is logging to error_log.txt turned off? Note in generated HTML code I have <?=$Com?></title which generates no errors, but later where if have

<?=$Topics[$Com]?> I get errors that $Topics and $Com are not defined, but earlier there was no message.

@Col_Boogie As suggested in your other thread.
Php short are not allowed by default.
You need to use universal style,

If you want to use short code then follow the below tutorial,

This should solve your issue.
If you still have issues PM me or Post back in your other thread.