You are seeing this message (also in the log of the WLC) because the level of interference for the 2.4Ghz radio of the particular access-point is higher than the configured (or recommended) threshold.
You can find this information on the WLC on Monitor -> Access Points -> Radios -> 802.11b/g/n. You can tune those threshold on Wireless -> 802.11b/g/n -> RRM -> General.
The question for now is how high are those values and do you have problems because of this and the answer to that question is; it depends. If you think the values are too high or if you experiencing issues I would go to the location with a spectrum analyzer and see if I find the cause of the interference.