Doc: Explains how to fix preg_split error in store.php

Fixes TiddlyWiki#3011

editions/tw5.com/tiddlers/saving/Saving on a PHP Server.tid

@@ -3,7 +3,7 @@ created: 20140111091844267
 delivery: DIY
 description: DIY script you can install on your own server
 method: save
-modified: 20171113105946993
+modified: 20171114212220389
 tags: Saving PHP
 title: Saving on a PHP Server
 type: text/vnd.tiddlywiki
@@ -41,3 +41,7 @@ As your TW file increases in size, you may need to modify  your `.htaccess` or `
 php_value upload_max_filesize 4M
 php_value post_max_size 6M
 ```
+
+!!! Note about possible error message
+
+If you get an error message regarding `preg_split()`, you may need to change references  to `preg_split` in ''store.php'' to function `explode` .