Could not login 500 internal server error phpList 3.2.4

cPanel Version 11.52.1 (build 3)
Apache Version 2.2.29
PHP Version 5.4.35
MySQL Version 5.5.46-cll
MySQLi [unknown, but should be whatever came with MySQL 5.5.4]

Architecture x86_64 Operating System linux

I installed phpList 3.2.4 (Release Date : 08 dec 2015) for the very first time using softaculous. I kept all the default options the same. I got a 500 internal server error when accessing my webpage /lists and /lists/admin index pages. So I have yet to actually log into phpList ever.

I asked my web host about this and they looked at some logs and they said:

The issue appears to be with the script, since it’s complaining about the missing module while it’s actually installed (MySQLi):

[Mon Dec 28 22:33:25 2015] [error] [client] malformed header from script. Bad header=Mysqli functionality missing: index.php
[Mon Dec 28 22:33:25 2015] [error] [client] File does not exist: /home/public_html/500.shtml

I can only advise you to try contacting the developer and let us know if they need any configuration updates from our end.

Any suggestions on what modifications need to be done. I checked your manual documentation but it does not mention the 500 error. I thought the softaculous auto-detected and installed everything correctly.

EDIT: the web host upgraded my server to php 5.5 and then it seems like now everything loads, no more 500 server error. So I have at least been able to login to the admin panel Since I already typed this maybe it will help someone. I’ll probably just upgrade to php 5.6 to be a little more future-proof. [any harm in doing that?]