Cubase Problem !!

[picato]

I think that I know what the problem is here. I suppose that you have a track with an audio file on, and that you have copied this file to other places in the same track, right?
The thing is that Cubase doesn't see these parts as different wave files! If you check the audiopole in the panels menu (I run VST32) you'll find just one audio file for every part on that track. No matter which part you reverse, you will reverse this single file, and then, everywhere in your arrangement where you use this file it's going to be reversed. Got it?
To solve this you'll have to multiply the file in the audiopole (copy and paste) and rename the copies so that the audio file you wish to reverse isn't beeing used unreversed on another track.
I'm not going to describe this in detail here, and I don't really know how to do it in your version of Cubase either. Check out the section about the "audio pool" in the manual. You could also find the audio file on your hard drive and copy and paste this to a new folder, then rename the copy, at last move it back to your wave folder and import this one to the track.