Moved some files - got strange results....

Im still learning Final Cut Pro teaching myself and have got stuck I think due to doing some file management...

I tidied up some files on my Video drive and put all the files needed for the project in one folder the large .dv file from the camera, and the intro movie I made in Motion. The Final Cut Pro Documents remained in the usual place with all the default stuff in there.

However as I opened the project today it needed me to locate the files post - move which I did no problems.

However for some reason all the renders I had done are gone from the 'Renders' file in 'Final Cut Pro Documents'. Ok well thats not the end of the world. I re-rendered one of the sequences - and there is a strange anomaly. The first intro.mov file I created in Motion is now not playing back/rendering properly. Its just a blank screen...
If I play back the file in the viewer Im using - it works fine. However when rendered it just is a blank screen - and pre-render - there is this strange red/white checkered box over an area where there should be a picture. I really dont want to have to completely start again.

Any ideas if there is anything that can be done aside from re-inserting the file again? I have no idea what happened...

Picture showing sequence in middle window - where pre-render file has strange red/white checkered box around it....You can see what it should look like in the viewer to the right:





Here is what it looks like 'post' render. - blank - and again what it should look like in the viewer to the right...





Thanks very much for any help in advance...