Unable to update version ...

Hello, I get this error message when typing svp update :

xxxxx@observium:/opt/observium$ svn update
svn: E155004: Run 'svn cleanup' to remove locks (type 'svn help cleanup' for det                                                       ails)
svn: E155004: Failed to lock working copy '/opt/observium'.
svn: E200031: sqlite[S8]: attempt to write a readonly database
svn: E200042: Additional errors:
svn: E200031: sqlite[S8]: attempt to write a readonly database

Thank you for your help