incorrect temperature readings (0 C)

All;

My Toshiba is always reporting a 0 C temperature – this is problematic since when the fan goes on, it stays on. ACPI utilities report:

THRM: temperature: 0 C
frequency: disabled
mode: 3
state: 4
Temperature: 0 �C

and dmesg reports:

ACPI: Thermal Zone [THRM] (0 C)
does anyone have any recommendations?
…Dan