I have same problem with my PHILCO PHN 15008 with ubuntu 10.04 b2 and 9.10. Mandriva doesn't has problem. When I use windows seven or only BIOS system or Mandriva 2009, everything is normal. If I load Ubuntu 9.10 or 10.04, the cooler turn off.
I used acpi.power_nocheck=1 and now the cooler turn on, but with very low rotation.
I use cored 2 duo + pm45 + ich9m. In the ubuntu installation, the same problem appeared.
Before use this flag, in normal situation with 20c ambient, core 2 duo was 90+ celsius with stress app (stress -c 2). After used this flag, i had 60~70 celsius. The critical is 97c and if the system getting there, the system (probably BIOS) turn off my computer.