[otrs] charset Problems?

Hi! I am running otrs 3.0.10 and I have problems with attachments (we choose file-based as storage): File '/opt/otrs/var/article/2011/09/22/132887/SUMO_Kick-Off_eCampus-Ankündigung.docx' doesn't exist! If I change the filename to SUMO_Kick-Off_eCampus-Ankuendigung.docx and in the content_type file then the file appears as attachment. Any hints? regards Martin