When he says chmod the files, it simply means to change the permissions on that folder. If you are doing it through a control panel, youll need to change them in your directory. If you are using an editor, you can right click on the folder, go to permissions, and the box will pop up showing you your settings. Just change those 3 numbers to 666 like Neo says.
That might be your problem.
I didnt have any problem with the modules, because they were added when I did the DEMO install. I chose to use that install because im new to joomla, too. So the more examples I have to go by, the easier it is for me to figure SOME of this stuff out, lol.
Good luck, hope I helped a little.