Error Writing Meta Data??? Confused

[RebeccaAPhotography]

I have a question for yal...

I noticed while editing in Lightroom 3 some of my photos have an exclamation point on the top right. I click it and it says error writing meta data.

It then gives me 3 options. 1) import settings from disk. 2) Over right settings 3) Cancel.

I dont want to lose the pictures and don't really get why I got these errors in the first place. What should I do to "fix" the problem? Also is there anything I can do to prevent that from happening again?

Thanks for helping!