Hi Daniel Lim,
- You get this error message when you try to install any apps or only the apps related to AVG?
- What is the complete error message?
htmlayout.dll is usually associated with malware.
You system may be affected by Virus/Malware, I would suggest you to run Microsoft Safety Scanner on your computer and check if it detects anything.
http://www.microsoft.com/security/scanner/en-us/default.aspx
Note: Any data files that are infected may only be cleaned by deleting the file entirely, which means there is a potential for data loss.
Please post with the required information.