I tried updating the control panel settings to internal and 2+ characters...but it still won't find the words "IRA" or "tax." I know there are posts that meet this criteria but it just won't locate any. Same thing the FullText method did. Is there anything else I can do? Thanks for your help.
That won't do it, it's a config entry for your MySQL server itself that needs adjusted (the setting in the UBB is just if you change this setting).
If you just turn your search setting to "Internal UBB Search" versus "Full MySQL Search" it'll fix the issue.
If you're adamant that you "have" to use the "Full MySQL Search" (as opposed to the other option of "Internal UBB Search") option then you'll need to go and do some research on the web for configuring your MySQL server to allow searches of less than 3 characters.
See the UBB.Wiki