Please note that I did not write this MOD. I was asked to upload it here by the author.
The following is part of the readme file that's included with the ZIP:

Message Icons MOD v3.4
by Anonymous
Developed for use with Snitz Forums 2000 v3.4.xx
Tested on Snitz Forums 2000 v3.4.02

Support:
I can not provide support for this MOD. But, you should be able to seek help from others in the following forum:

http://forum.snitz.com/forum/forum.asp?FORUM_ID=94