Uploading RIX file into Windchill 10.0

Bit of a Windchill newbie, so go easy!

I am trying to load an older prediction into Windchill 10.0 - I believe the previous prediction was created using an older version of Relex, not sure what version though. The prediction was created by a colleague before he left. He saved a copy of the prediction onto the server and it is showing up as a RIX file.

Can someone enlighten me as to how to import this RIX file into the software? I've tried using the Import/Export wizard, but that only seems to upload gibberish.

Thanks.