Website help

Another website help question:

I've registered a domain name with 123 reg
And built a website using Wix
(it's http://www.ridesidebyside.org )

Site will be changed to look better when I have time

123 reg doesn't seem to like the fact that I have redirected the nameservers from 123reg to Wix which seems to present a security issue

Please note: Your DNS is not currently set to the 123-reg nameservers.
To use the 123-reg DNS service, your domain must use the default
123-reg nameservers Our systems have detected that ridesidebyside.org
uses the following nameservers: ns8.wixdns.net, ns9.wixdns.net.

I'm a complete noob at this (Have used @velocio for this techie stuff for my earlier websites)

Any suggestions (I utfs on both Wix and 123reg and came up with nothing

Thanks!