how do i get the smell of dog wee out of a carpert it smells like a musty smell so i guess thats what it is

It may still be possible to remove the smell but as you're unsure if it's dog wee or not then presumably you didn't see it happen - rather than simply not cleaned it up sufficiently.

Using biological soap powder dissolved in warm water ususally does the trick and wipe over with white vinegar / spirit to break down any remaining fatty deposits.   Chances are if this is a late clean up that the urine will have seeped right through and onto the underlay in which case it's unlikely that you will be able to remove the odour entirely :(   If possible lift the carpet and clean the underlay in a similar fashion - but again the later left the more likely it is that the smell will remain.

good luck!  Teri :)

the best i have found is good old bio washing powder, its the only thing that seems to break down the amonia, there are special sprays from pet stores but i still come back to the washing powder/liquid just make a fairly strong solution of it and work into the carpet blot off as much as you can so it dries quickly, if its a faily old stain you might need to repeat it a couple of times, try an area that is un seen first as it can lift the colour from some carpets
Regards
Pauline