Moved to InDesign forum.
Not nearly enough enough information to even begin to help.
1. Are you patched to 9.1?
2. What operating system are you using?
3. Does this happen with all documents or just one?
4. Have you tried trashing your preferences?
To answer your Qs:
1. Yes, i am using v9.1
2. Mac (os 10.7.5)
3. Several docs
4. No, i've changed my prefs (expanded pasteboards) for several files. I'm not sure how trashing my prefs will affect these files. Would appreciate your help on this one. Thanks in advance.