How I got it to work: Use some code from browse.php.

Segment:

else {
	if($searchtype == "simple") {

Replacement:

else {
	$disablesorts = array( );
	if($searchtype == "simple") {

Segment:

  </select><br /><br /><label for=\"searchterm\">"._SEARCHTERM.": </label><INPUT type=\"text\" class=\"textbox\" name=\"searchterm\" id=\"searchterm\" size=\"20\">

Hit enter after that line and add this (this is to keep the Sort drop-down menu spaced out from the Search Term textbox):

  ";

Segment:

  <label for=\"sortorder\">"._SORT.":</label> <select name=\"sortorder\" id=\"sortorder\"><option value=\"alpha\">"._ALPHA."</option><option value=\"update\">"._MOSTRECENT."</option></select>";

Replace with this:

  if(!in_array("sorts", $disablesorts)) $output .= "<label for=\"sortorder\">"._SORT.":</label> <select class=\"textbox\" name=\"sort\"><option value=\"alpha\"".(!$defaultsort ? " selected" : "").">"._ALPHA."</option><option value=\"update\"".($defaultsort == 1 ? " selected" : "").">"._MOSTRECENT."</option></select>";

after i managed to make my account i checked on my site and saw that you've released 3.5.83 and tried to install it but it threw up an error so i thought you'd like to know. 

This is patched on my own fork, but just letting you (and anyone reading this) know.

Amusingly, I triggered this by accident a few days ago by testing random repeating characters, and they happened to be the percent sign, lol. Confused me for a moment, like the nonexistent co-authors Error 500 PHP 8 bug in includes/userlist.php I ran into nearly two months ago.

I have set up UwAmp with Apache 2.4.69-x64, MariaDB 12.3.3, PHP 8.1.34 and phpMyAdmin 5.2.3.

I downoaded "https://update.efiction.org/v3/3.5/efiction-3.5.72.zip" from the link in the post above, but as soon as I opened the link "http://localhost/efiction/install/install.php" I get what you see in the attached screenshot (it's just a part of the screen).

Can you help me with getting this installed, please?

I have added another screenshot of the homescreen after starting the local webserver.

This was a bug in our installer, not something you configured incorrectly in UwAmp. The installer was loading language files before initializing the settings they depend on, which caused those PHP warnings.

I've released eFiction 3.5.81 with the fix:

https://update.efiction.org/v3/3.5/efiction-latest

Since you're doing a fresh installation, extract the new package into a clean folder and open http://localhost/efiction/install/install.php again. You don't need the standalone upgrader for a new installation.

If you've already added any content, back up the files and database before replacing anything. If you still get errors with 3.5.81, please post the first error and which installation step it occurs on.

I have set up UwAmp with Apache 2.4.69-x64, MariaDB 12.3.3, PHP 8.1.34 and phpMyAdmin 5.2.3.

I downoaded "https://update.efiction.org/v3/3.5/efiction-3.5.72.zip" from the link in the post above, but as soon as I opened the link "http://localhost/efiction/install/install.php" I get what you see in the attached screenshot (it's just a part of the screen).

Can you help me with getting this installed, please?

I have added another screenshot of the homescreen after starting the local webserver.

I also ended up deleting my poll from the database and the poll from the index.tpl. But that just masks the problem, updating the php to fix the underlying problem is always the better solution. :)