Streaming Real Audio

Hello,
I am new to PHP and trying to learn developing websites using it. One of the script I am trying to create is "Play Selected" to play the songs that user selected. I reached a point where I can identify the songs that user selected and want to create an SMIL file. Reason I want to do this is because I am using a popup window with real media player embedded in that window page. The embed tag requires an SMIL file as input, to play all the audio files selected in the list in sequence. So my problem is
"When I tried to create the file on the server with in a php script, permission is being denied. Somebody told me that I should create the SMIL file in client's temporary internet folder and specify that file as input for SRC parameter ". I would appreciate if anybody can suggest any solution or point me in the right direction if I am missing something obvious?
Thanks,
Raj