Having problems w/ my Toshiba SD-3960 (has trouble playing Warner Bros. DVDs)

I bought a Toshiba SD-3960 for a fairly cheap price but I still thought it was a decent player because I've heard good things about the brand Toshiba. I don't remember having this problem when the player was new but the problem is definitely there now. The DVD player is about 18 months old and has a lot of trouble playing Warner Bros DVDs. With the older WB movies the player vibrates a lot at the beginning of the movie but stops vibrating about ten minutes in. With the newer WB movies and also some New Line DVDs it makes a weird sound when loading the DVD. It sounds kind of like glass cracking slowly, it's really weird. I havent had any real problems with New Line DVDs but in addition to the strange sound while loading, Warner Bros DVDs tend to freeze up, like a layer transition, only it does it about five times throughout the film and it only does this with Warner Bros DVDs. I'm probably going to buy a new player anyway but I'd still like to know what is wrong with this one.