Instructions to splice the 2 parts together:


Get virtualdub at http://virtualdub.sourceforge.net/. We recommend the stable version.
If you do not have a DivX decoder, get it from http://www.divx.com.

Open Part1 with virtualdub. Then, do File->append AVI segment, and load Part2.

Set Video->Direct Stream copy.
Set Audio->Direct Stream copy.

Now, do File->Save as AVI.

You should have the whole movie in a single file now.