yeah it's an ARCSOFT issue. It happens to me as well. Its just something you are gonna have to deal with. ARCSOFT is the best program....because of the addition of picmail.
But you could always try this. Its a contact app but it has threaded SMS build in. It will replace your contacts softkey on the Today screen so it shouldn't be hard to get to.
PocketCM-0[1].29.cab.zip