To add a file/folder to the project, a good way is:
First of all add your files to /path/to/your/project/my/added/files, and then run following commands:
svn cleanup /path/to/your/project
svn add --force /path/to/your/project/*
svn cleanup /path/to/your/project
svn commit /path/to/your/project -m 'Adding a file'
I used cleanup to prevent any segmentation fault (core dumped), and now the SVN project is updated.