The error seems to occur only when using an old X-Server (vncserver based on XFree 3.x in my case). Installing version 2.6.2-1 fixed the error (I made the check and reinstalled 2.6.1-2, which made the error reappear).
I think this bug report can be closed now. Thank You! -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]