I am running mepis 11 64 bit with ktorrent 4.0.2, recently i was searching for something and one of the search engine choices sent me to a bing search page. Ever since whenever I start ktorrent a number of .js files are downloaded from bing.com to /var/tmp/kde-User, while they are DLing Ktorrent is unresponsive and unusable, sometimes to the point of needing to logout of the user session and log back in to get control of my desktop back. How do I stop this unwanted behaviour

Can you check the KTorrent settings to see if it has a nominated search engine? If it does, try changing this to something else.
Also, please try to reproduce this behaviour under a new user.