Thanks, Dan. I've done it many, many times with no problems, but in those instances, I did the differential correction of the raw data myself. The procedure I use is :
-In Utilities menu, choose "Export..."
-Browse to the .COR file I want to export and choose it
-Browse to and choose the output file I want
-I already have all the Properties checked that I want, but I did double check those, just in case
-Then I press "Ok."
-It always prompts me to remind me that I don't have a coordinate system chosen (I leave WGS 84 as the default, then define it in Arc because I've had better results doing it this way), so I just tell it to continue and then it exports.