USRP2 error failed to enable

Hi all,

I have successfully loaded gnuradio and gnuradio companion onto Ubuntu
9.04 and i am now testing the usrp2 with the 400mhz transciever daughter
board. I run and the gui pops up and when i input a signal
it appears on the FFT graph. This is great!

However in the terminal the following message pops up

usrp2:failed to enable realtime scheduling

I am curious because it appears to be working but this still comes up.
Is this affecting performance? Do i need to change something?