Hi Junkone
Hope you didn't get impatient without an immediate answer!
Sounds like Cuchulain might have the answer if you don't have Picasa 3
I use a K20D (still with Ver 1.01 software). I shoot .PEF and use Picasa 3, and don't get a blue cast.
I think that although Picasa opens .PEF files it still applies the camera settings so you might have camera set to "tungsten" or a custom Kelvin setting.
I do know that Picasa does a lot of editing to even a RAW image as my sunset, night sky and under-exposed bloopers are always too pale as Picasa tries to normalise them; and thats before you start playing about with the auto-contrast etc buttons.
The Picasa editing is why I use it as for normal exposure images it saves me having to edit each RAW file, but I still have te raw if Picasa can't handle it.
I'd suggest opening them in Pentax Photo Browser, probably downloadable if you haven't got it, which tells you what settings you took them with.
QS