Audio Loops

I've had a couple instances where placing multiple instances of an audio loop in a track has resulted in the whole of my project creating terrible noises.

Last night I put in a single cymbal crash and it worked fine, when I added a couple more, Sonar started making loud electronic noises throughout the project. I used Task Manager to kill Sonar and restarted it, but it still did it with every project until I rebooted. Then everything was fine.

Any tips or pointers with loops? Are some loops just evil? I have used loops from this same vendor before with no problems. Now I'm leary of picking any from this particular set. Is this a common problem? I have so few problems with my system that this event stands out.

Daryl

Sonical Labs R6600 Duo Core Workstation - 2GB Memory
Windows 64
E-MU 1820M
Sonar Producer 6.01