NUance, what are you searching for?
One simple thing that seems to screw up searches is a space at the back of the search term. For example, I frequently search user names to put the accurate name in the Starting Lineup polls. Someone nominated jsneb83 but wrote his name as "jsne." Without a period at the end of their sentence, the board software defaults a space at the end of a blank sentence, so when I did a copypasta to get the correct spelling (and capitalization, number, whatever) it originally kicked back a "Your search produced no results." I had to delete the space after "jsne " before it would work.