Please check your antivirus/firewall logs.
Make sure you created exclusions for both the trainer exe and the 'Work' folder in this newly created location -> C:\Users\YourWindowsUserName\Cheathappens\
If necessary create firewall rules again for the trainer and the file '~CheathappensTrainer.tmp' in the aforementioned location to have access via TCP port 80.
Please make sure that you exclude the trainer exe and the -Work- folder in this location -> C:\Users\YourWindowsUserName\Cheathappens\ from any AV/other security software scans and run the trainer with admin rights.
You are mixing up Skill Points and XP.
From the instructions/readme provided with the trainer:
To add/edit your EXP open your progress screen first, then make changes.
Unlimited Skill Points:
You must have at least 1 skill point. Go to attribute page and activate this option.
Then you can spend as much points as you want, press apply. Deactivate this option.
Please note that after you do this it will set your skill points to zero but the
attributes stay unlocked.
Same thing is happening to me. I can confirm it happens with the XP and not with the skill points.