I was getting the following error in server logs :
Cannot accept non-LF line endings in 'svn:externals' property
It seems that since I am using TortoiseSVN for loading the properties through a text file, there were some invalid characters in that file.
To resolve the issue, I removed the single junit 4.10 SVN:externals entry from SVN properties displayed for the directory, instead of removing the line from text file and loading the file again.