Here's a common scenario I've seen cause a lot of people headaches. It's possible that you might be in this state:
- Working Copy is in broken state. SVN
complains that file 'bar' under 'foo'
directory is causing problems.
- Developer makes a backup copy of the
foo directory.
- Developer deletes foo dir from working copy.
- Developer does svn update, foo and
bar are reverted and svn is happy.
- Developer copies backup copy of foo
back over into working copy and svn is no longer happy and no longer able to update and/or commit
The fatal mistake here was when the developer made a backup of dir 'foo', they also made a back up of all the hidden ".svn" directories nested inside foo.
So, the solution (in my experience), is to use tortoise svn's "export" capability to make a backup copy of foo. Tortoise svn Export will create a copy of the directory structure without any svn meta data (.svn dirs). This way, once you're back to step 3 and svn is happy, when you copy your backup back into your working copy directory, svn should be able to capture the changes correctly.
Then again, if it's only a single file you're creating a backup copy of, then, this won't help.