CurrentTemperature does not exist - it is CurrentReading.
But I have more bad news for you: that probably won't work either.
See MSDN: Win32_TemperatureProbe class
"Most of the information that the Win32_TemperatureProbe WMI class provides comes from SMBIOS. Real-time readings for the CurrentReading property cannot be extracted from SMBIOS tables. For this reason, current implementations of WMI do not populate the CurrentReading property. The CurrentReading property's presence is reserved for future use."