If I remember correctly, the main problem in apps other than Photoshop (6.01 CE in my case worked fine. see that red-, gold- and red-white-blue-coloured banners in the gallery) seemed to be that the tiff was saved compressed, so tiff2pgm couldn't read it. So, TS, if you're working in Photoshop, check Advanced TIF options to get uncompressed TIFs. I don't know what to do in other apps. BTW, since I'm currently trying out an app called Photogenics, which supports HDR, I'll try creating a 16-bit tif and report what happens.

-- erlik