Based on what you said, I am guessing that you are successfully creating the files? In other words, have you double checked via FTP that the files are being created?
Are you accessing the files with the same case? Remember, Linux is CaSe SeNsItIvE, so Something.txt is different from something.txt .
Also, you should not chmod the files to 755 unless they are CGI files that you are executing as programs (which is 99.9% not the case). If you want to simply have read access to the files then 644 will work. If you want to have read / write access then 666 will work.