I had a portrait that the client wanted in a sepia tone, went to my Nik Silverfast 2 and got it just right, when I got it back into photoshop, the sepia was gone- WTH is going on here??
I may be totally wrong since I am not familiar with that software (Silver EFX) but you may not have the original in a format that PS can read. I had a somewhat similar situation having taken some photographs in Nikon RAW (D300s). I had to use the Nikon software to convert to a TIFF first. Perhaps the NIK software works with the capture software and PS doesn't. I have SilverFast Studio scanning software and it woks just fine with PS CS4. Check to see what format the image is in NIK it may be a simple correction.
I spoke with a guy who prints digital for a living- he has had similar problems, so we decided it was probably in the NIK program. I got it fixed, don't have a clue how, except I re booted the program a time or two.