From AMSN

tkDND is a Tk extension to let developers add Drag and Drop capabilities to their Tk-powered applications.

aMSN uses TkDND to let the chat window accept dropped elements. This way you can drag and drop a file over the chat window and send it right to the contact your chatting with.

Windows

• Download this file : http://prdownloads.sourceforge.net/tkdnd/tkdnd-1.0a2.tar.gz?download
• Extract it, then move the subdirectory tkdnd-1.0a2\lib\tkdnd\ into amsn\scripts\utils
• Download now this file http://prdownloads.sourceforge.net/tkdnd/libtkdnd10.zip?download
• take the libtkdnd10.dll from the package, rename it to libtkdnd.dll and overwrite the one you just placed in amsn\scripts\utils\tkdnd

Linux

Fedora Core users reported the package tkdnd is available for tcl8.4 so you'll just have to fire up your package manager and install it.

For Debian based systems (including Ubuntu), you'll have to do a little command-fu. First, go to sourceforge and download the latest i386 rpm file. I know, you thought that you were done with rpms, but... you're not.

Open up a command line and issue the following commands as root in the directory that you downloaded it (probably ~/Desktop):

  apt-get install alien

  alien -d tkdnd*.rpm
  dpkg --install tkdnd*.deb

There, restart aMSN and you should be able to drag and drop.