Not being able to copy files from pendrive to linux ( it says permission denied)

[Shreez]

Error opening file
Permission denied

[mikahawkins]

In Ubuntu / Linux, files are hidden by placing a dot prior to the file name. There are possibilities that copied files are hidden. Try hitting "ctrl + H", to show hidden files. Convention of making files hidden by placing a dot(.) prior to file name is not recognised by Windows, so it will display it as a normal file. Example of hidden file name in Linux is as follows <.file_name>. Here I am assuming any file system related compatibility exists as pendrive is being detected and you were able to copy files to them and I also assume that these copied files are intact in Windows.
Hope this helps !!!