Updating the working copy should fix it.
From the command line:
X:\WorkingCopy>svn up
or right-click and choose SVN Update... in TortoiseSVN
When you update, you may come across conflicts, which will be marked in your code with
>>>>>
...
-----
...
<<<<<
You’ll need to manually resolve these. When you’re done, don’t forget to mark the file as resolved.
X:\WorkingCopy>svn resolve \path\to\file
or right-click and choose TortoiseSVN -> Mark as Resolved... in TortoiseSVN