Version: 0.8.1 (using KDE 4.2.1)
Installed from: SuSE RPMs
When opening a pdf file by left click in a file manager like dolphin or konqueror, okular starts with an error dialog (file with filename xyz can't be opened), if the filename contains at least one german umlaut.
Using the menu File->Open... the same pdf can be opened without any problems.
*** This bug has been marked as a duplicate of bug 186038 ***