Last modified: 2005-07-08 09:55:59 UTC
On the page http://pl.wikipedia.org/wiki/Grafika:De-Köln.ogg the first text "De-K�ln.ogg" is an empty link (view source: <a href="" class='internal' title="De-K�ln.ogg">De-K�ln.ogg</a>). Perhaps this has something to do with the umlaut. I didn't check this with other examples.
Not specific for wp-pl: see also http://de.wikipedia.org/wiki/Media:De-Köln.ogg
http://commons.wikimedia.org/wiki/Image:De-Richard_von_Weizäcker.ogg
Seems to be fixed (since 1.5 upgrade?)