Hi donaldt,
I can't say i know for sure without seeing how you are entering the date in your input, You'll need to make sure it's the same format as that in the DB since some don't use hours and seconds, some use time zone etc...
here's some code I've used before.
querystring = "select * " & _
"from request_received " & _
"where start_date < " & input1 & _
" AND " & _
"end_date > " & input2
I fully recommend you hardcode into the dbms first and get the query working with constants, THEN put the variables in, it should work then without hitches if you get constants to go in.