Once you download SVN 1.7.15 (the version is very important). You can right click your project folder in file explorer and go to tortoise svn > check for modifications.
Then you will get a pop up window where you would see a list paths in your project. The conflict will show in the status column and will say conflict. Right click this row and choose resolve using yours or resolve using theirs. Resolve using yours will use your copy of the code. Resolve using theirs will use the team servers copy.
Hope this helps!
Are you sure you have the correct version of TortoiseSVN installed?
You’ll have to use version 1.7.15 for Mendix related SVN actions.
You can use TortoiseSVN to resolve conflicts on disk. You can Right click in your project (in the windows explorer) and use the TortoiseSVN options to solve the conflicts.