Can't access Dropbox folder

[user1]

>> It would have been helpful if you had told us which you had tried.
>> What about this one?
>> 
>> http://askubuntu.com/questions/247461/how-do-i-fix-a-cant-access-
> dropbox-folder-error
>> 
>> Colin
> 
> Yes, I have tried that one, seems to make it take longer before the
> error message appears.

I rebooted my pc and Dropbox is okay and after running for about 2 days 
the error message is back again ?