Galaxy S issues

Hey guys!  I've had my Galaxy a little over a month and I'm wondering if anyone is having the same issue(s) that I'm having. 

 I loaded some music onto my phone to use as ringtones/notification tones.  Sometimes the tones work, but sometimes they don't and I have to restart the phone in order to get them to work.  It's the same thing with the video camera; sometimes it works and when it doesn't work, I have to restart the phone to be able to record video. 

My husband (who uses a BlackBerry) looked on my phone and said it seems to be running out of RAM.  Has anyone else had  this problem and if you did, is there a fix for it?  I've already had to exchange my 1st Galaxy for a new one because it was acting crazy and at this point, I'm about ready to go back to my BlackBerry!  

OK...so...not really.    Anyway, thanks in advance for any insight you can offer.