I was also having this problem after having successfully used iTunes Match previously. The problem appears to be when there are two version of songs and one of them has the iCloud icon made using a dotted line. Here's what solved it for me:
1. Identify your duplicate files. I have a large library, so I elected to use Dupin Light (available on the Mac App store). I suppose I could have used iTunes duplicate finder too, but I prefer the flexibility of Dupin.
2. Once you have identified your duplicates, find them in iTunes. In my case Dupin identifed 50, from 19,000+ tracks, so for me it was not a large number to check manually.
3. When you find the duplicates, if one of them has the aforementioned dotted line iCloud icon, this is the one you need to delete. If you accidently delete the other version, you can always download it again if you have purchased it from iTunes. In any case, it seems to be the tracks with this icon that it is causing iTunes Match to stall, so you will need to delete all of these.
4. Once you have completed step 3, iTunes Match should not proceed and complete.