hi xenon..
bit of prob here.. or maybe not.
I have your hack installed on my site. Now prob was that 1 month back i moved to site running php as cgi. Now i did some changes together with my host(No code change though) and have it working on my site in origianl form
like here
http://www.techenclave.com/forums/search/
Now i saw that google is crawling it too. Have the google sitemap integrated on forums and changed its code to use this forums url instead of stock archives.
But i just had a look at google today... and i see this :S
Google Search
err there are whole lot of urls there but no description at all...

i checked other sites running your archives like
http://www.howardforums.com/archive/
and
http://forum2.youceff.com/search/
and for them when you do a google query
you get results as
Result1
and
Result2
Now as you can see they have descriptions also in the results...
Now what am i doing wrong or exactly whats the cause of this prob.