Questioner:
Is it a requirement for a person to have wudoo, for the supplication to be answered?

Answer:
It is not a condition for supplication to have wudoo; It IS worship, however there is no condition to have wudoo or to be in a state of purity.

Source:
http://www.alfawzan.af.org.sa/sites/default/files/14330102_13.mp3 .