Version: (using KDE 4.2.0) Installed from: Unlisted Binary Package Not much to say... set urxvt as default terminal in kde. Open up e.g. dolphin and hit f4 to open the terminal. Trying to paste something with the middle mousebutton wont paste anything.
Can you still reproduce this on the latest stable KDE version?
I tried this with KDE 4.5.5 and couldn't reproduce the issue (with urxvt). Previously mouse-selected items could be pasted in urxvt, e.g. manually selected text in the rename dialog. Notice, that pasting with middle mouse click uses the X clipboard, which is distinct from the KDEish copy-paste thing (not sure why there are two clipboards on linux, but this is a different issue). Please reopen, if you can reproduce the bug on newer versions, but keep the above remark in mind.