The file looks like it is there in the folder, have you logged into your sever via FTP to see if it is there? You should also be able to browse directly to the file that is on the server. The installer script is just looking for the file on the server so if it is there it should find it. If after confirming through FTP and by browsing to the file it still does not work for you let us know and I will open a ticket for you so we can look into this further.