You will see a number of 'access denied' messages after installation in portable mode when trying to perform operations such as opening projects or accessing documents.
You have installed CE in PORTABLE MODE, in this mode CE is installed under one folder, the program needs read and write access to all the subfolders but deosnt have it. The permissions on the folders will depend on the operatating system and who you were logged on as when you installed the product.
Switch it back to default mode. This will remap the working folders of Community Edition to the current users file area under c:\users (for Windows 7).
To switch it to Default mode
NB Portable MODE is designed to work with a file system that does have full read and write access to the installation folder so will work perfectly on a standard USB memory stick