Attempting to save playlist to a write protected directory gives the message :-
"Note: The name you chose is already taken. Please choose another name for your 
playlist, or check 'confirm overwrite' to replace your existing playlist. "

Followed by a "Save as' and overwrite dialog.

The assumption seems to be that if a playlist can't be written then it is
because the list already exists and can therefore be overwritten.

A write permission test for the directory needs to performed at some point
during the save operation.

Problem occured when saving from web interface running on an XP machine
to slimserver running on linux FC2.