When subversion modifies your working copy (or any information within the .svn), it tries to do so as safely as possible. Before changing anything, it writes its intentions to a log file, executes the commands in the log file, then removes the log file (this is similar in design to a journaled file system). If a subversion operation is interrupted (if the process is killed, or if the machine crashes, for example), the log files remain on disk. By re-executing the log files, subversion can complete the previously started operation, and your working copy can get itself back into a consistent state.
In eSvn use the Cleanup option to recursively clean up the working copy, removing locks, resuming unfinished operations, etc. The operation is performed on the item selected in the Folder or the File View