What does their Realtor say? What does the feedback say? If they aren't getting any showings, then it's likely a price issue. If they're getting plenty of showings, but no offers, then it could be price, or something else. Location? Floorplan? Paint colors? Carpet? Showing condition? Decor? Too hard for anyone here to give you a definite answer. I'd ask the Realtor to do another CMA and see what has changed since it's come on the market. What has sold, what's gone under contract. I'd also look at the feedback.
I had listing that got a ton of showings, was priced well, good location, etc. and feedback was generally good, excep the paint color throughout the whole house was a horrible orangy/peachy color. Awful. Sellers refused to change it. I ended up losing the listing because it never sold, and they never listed to me. If people refuse to change things to attract a wider audience, then they need to accomodate for that somehow -- usually a price reduction.
I've also had a listing that had horrible dark blue carpet. Tons of showings, and feedback was the same. Carpet color was bad. Seller spent a fair amount of money to have carpet replaced, but we had an offer the next week.
And then on the VERY STRANGE side....I had a listing that had tons of showings, great feedback, good price, location etc. Couldn't figure out what the issue was. One day the seller asked me "Do you think it might have something to do with the fact that the previous owner died in the house?" Bingo! He hired a "shaman" who "cleansed" the house, and got rid of the "spirit" of the previous owner. Next week we had an offer. Seriously!
It could be any number of things. If you need the name of a good Shaman, let me know! :-)