I'm not sure why but for some reason none of the OpenEXR files I generate using the 3d packages Maya and/or XSI can be opened by XnView B5. The files open fine in Photoshop or Digital Fusion.
I keep getting the error,
" Format of the file <Yada> could not be determined. "
1.84 seems to have the same problem.
If you need files to test on.. Lemme know..
Oh.. thanks for the Gamma feature for OpenEXR..
I just wish I can test it soon

Cheers,
wOLV.