I installed Ubuntu 10.10 on a 13 inch MacBook Pro, and I'm experiencing a weird issue:

My laptop doesn't seem wake up after entering sleep mode. I'll close the lid and see the LED pulse. Then I'll open the lid and nothing will happen. The LED stops pulsing, but nothing else happens. In fact, even if I hold down the power button, nothing happens. I have to give it time (5 minutes?), then hold down the power button, at which point it seems to do a hard shutdown and is again usable when I restart it.

Some more notes. I'm currently triple booting (OSX, Win7, Ubuntu) and installed REFIT.

Honestly, I don't even know where to start looking for the problem. Are there diagnostic tools I could use? Is there any sort of logfile I should look for?

Any ideas? Help would be greatly appreciated.