UPDATE: I posted a new file in the attachment above. This should fix all the XP loading issues as I finally figured out the true cause of it.
If you STILL have problems please turn on debug mode and look for a line like this after a player connects and/or map changes
Code:
[AMX] SHERO DEBUG: "jtp10181<2><STEAM_0:1:19753>" Loading XP using key: "shinfo.STEAM_0:1:19753"
Please show me this line for someone who is having the loading problem.