HTC HD2 cannot open the file "screenoff". Maybe it was not signed with a trusted certificate. I haven't understood it for a long time.
Install a software called "BsB Tweak". The latest version is 1.6. There is a Chinese version. Please download it online. This is the fine-tuning software of HD2. There is an option called "Allow unsigned applications". Just click on it and restart it. If the English version is used, this option is called "Policy" and described as "Allow unsigned applications".