Add troubleshooting section.

README.md

@@ -19,3 +19,24 @@ Here's an LZMA-compressed copy of singleplayer as it was on 23/6/2022:
 https://mega.nz/file/nIpHDAbY#zLH1SyzNTU5y0elAJqU9rEGL1nVoAoFLxpyACod8QFI
 
 You should be able to extract this with something like 7zip on Windows. (It'll probably require two steps - tar.xz decompresses into .tar, then you extract the tar, both steps with 7z.)
+
+#### Troubleshooting
+
+##### My character's stats are decreasing after each login**  
+You changed your profile's XP rate to way higher than what is supported. Maximum supported XP rate is `5.0` for normal players and `10.0` for Ultimate Ironman players. There are no plans to change the maximum supported XP rates in the future. *Requests to change it will be ignored.*
+
+##### The console log keeps repeating `Still waiting for the server to start...`**  
+There are two known things that can cause this:
+ - You have extracted the files to a path containing spaces, e.g.: `C:\Users\My Name\Documents\2009scape`. Move the directory someplace else where there's no spaces in the path.
+ - The MySQL server has failed to start. Make sure there is no `mysqld.exe` in the Task Manager and that there are no other database systems running in the background.
+ 
+##### The MySQL server says `bin\mysqld.exe: Can't change dir to '<path>' (Errcode: 2  "No such file or directory")`**  
+You have moved the game directory after launching the game for the first time. To fix this:
+1. Close the console log to shut down the server software.
+2. Locate `db/data` directory.
+3. Edit `my.ini` file located therein:
+    1. Locate line `datadir=<path>`, where `<path>` is the path displayed by the error message.
+    2. Change the part before `/db/data` to the path you have moved the game directory to.
+    3. Save the file, close your editor.
+    4. Restart the server.
+4. The server should now start properly. If it doesn't, verify the path you entered is correct.