Problem:

During the installation process you see an error that states 200: SyntaxError: Invalid Character

Cause:

To complete the install process Checkbox needs access to C:\windows\temp. When you initially install IIS on your webserver this folder permissions should be granted access. If permissions are ever removed/reverted/restricted then this error can occur.

Solution:

Grant access to the previously referenced c:\windows\temp . Next delete your database and create a fresh db for install. (The failed install process can start to modify your database and create tables which will cause an issue on your second installation attempt).