Forum search broken?

[CuteLittleFaery]

I just noticed that the forum search function seems to be working very oddly all of a sudden; search results are seemingly limited to threads that date back about six weeks to mid-July. A quick examination reveals that the older threads still exist (dating back to 2005), but the search function seems to ignore them, regardless of what the "Search Previous:" field is set to. Any idea what could be causing this weird behavior?