Version:            (using Devel)
Installed from:    Compiled sources
Compiler:          gcc version 4.1.2 20070214 
OS:                Linux

Often when I download a (*.pdf) file from the web, konqueror will not start the download or will stall the download at some random point. The same holds true for other applications. (E.g.: Open a remote (online) file with okular and try to save the already opened file to the harddisk). 
Sometimes cancelling the download and starting from scratch works (or makes the download stall at some other random point).
I attached a little video showing the behavior when I wanted to save a remote *.pdf that I opened with okular to the local harddisk.
Maybe it is noteworthy that none of the buttons in the download dialog worked. (only the "x" and minimize button in the upper part of the dialog)
P.S.: Of course there is enough space left on the device.
P.P.S.: Trying to save the file to another location does not help.