Have you even looked at what this ICMP type 11 is? If you had just used Google, you would have found out that this is:
Type 11 Time Exceeded Used in traceroute, probes
So probably your IP is being probed, but since you left out all the IP details it is impossible to say whether there's probing from inside your LAN or from the WAN side.
Anyway, the error itself is absolutely not something to worry about and you should be thankful you're router is functioning like it should!