vista and resizing partitions

[DangerIsGo]

Ok so I got vista and wanted to play around with it, so i installed it on a 15gb partition (wasnt gonna do much with it) but i realized that 15GB is too small. heh. My 160GB drive is like this
80GB - XP
15GB - Vista
60GB - important/non-raided storage

What I wanna do is add another 5-10 GB from the important storage that isnt being used. I tried the vista disk manager and tried to shrink the non-raided storage (its a Basic drive) but it keeps giving me an error saying to check the system event log for more information on the unexpected error. I dont know what to do? Does anyone know any partition managers that work with vista? Partitionmagic 8.05 from symantec doesnt, it sees my drive as BAD. Any others?