Mouse and magic trackpad panels disappeared from System Preferences

[Taxer]

The mouse panel and the magic trackpad panel have both mysteriously disappeared from System Preferences on my Mac Pro running the latest version of Snow Leopard. I would like to restore them so I can adjust settings. I've tried restarting the machine and have reset the SMC and PRAM but no luck. Anyone know how to fix this?

Thanks in advance.

 

[RafaelT]

Not sure if this would help but have you tried repairing permissions?

 

[Taxer]

Thanks for the suggestion, RafaelT. I tried that (after you suggested it) but alas still not luck.