Corrupt EXR files

[Shimakaze]

I just finished rendering a 10000x5000 pixel picture to raw EXR. When trying to open it though it turned out to be corrupt. The size of it was only half of what it should have been as well. So I tried again with much lower quality settings and hiding lots of objects. Same thing happened again.
In the end I had to render to vrimg to get it out at all.
SP2 bug? I didn't change any settings that would explain it (not that there are any settings to change).

[vlado]

Works fine here for lower resolutions; what are you opening the .exr file with?

Best regards,
Vlado

[Shimakaze]

Photoshop with both the standard OpenEXR plugin and ProEXR. Same result for both. (AE can't open any EXR files at that size on my system)
Other then the file being at least half the size it should be, opening it in a hex editor shows it lacks some standard EXR information like the channel list at the beginning of the file.
Rendering smaller pictures work fine.