Can somebody tell me what's happening with my Internet Download Manager?

Recently, when I go to ANYSITE and download a video using IDM get video link function, my Internet crushes (some time it dosen't) and i can't go to the internet again unless i restart . I can't understand. It's not serve problem because once i restart the computer, the internet works fine. When i resume download, the internet crashes again. And when i restart the computer, there is a message board appears and says: that window is trying to end some not responding program called :"nsAppshell:EventWin" so something. Can somebody tell me what's happening.

Thanks!