Hi Chris,
I get this problem a lot after I had to re-arrange our backing-up process at my current company. Sometimes even moving a file from a folder to a sub-folder can cause a file to go offline. It is strange if it keeps recurring though as once youve connected the files to the current location then it should stay online. Sounds a silly question but do you save the file after youve reconnected the files?
As for the error message, I would ignore it. I often get this error message when I know the media that is offline is the original file from the bin or timeline. I don’t know why it does this but I would disregard it. You can always select Try Again and if nothing happens then just press continue. I’ve found that if you are actually re-connecting a wrong clip then a second error message will come up alerting you to this (although the actual message evades me at this point) and before you press connect, the wrongly connected clips will appear in italics in the bottom window, as opposed to standard text.
Hope this helps.
Danny