Is the netgear surboard a modem only or a modem/router. Most modem only do not have wifi on them so you can only connect via ethernet cable.
A repeater uses a hack called WDS to make it function. It is considered a security exposure and is disabled on many routers and must be configured on others. You need to check your netgear box and see if you must manually enable WDS. You may also have to put in the mac address of your linksys.
It generally is not a good idea to use any form of wifi repeater unless you have no other options. It tends to have a huge performance penalty and now you have 2 radio signals that can take interference. You would only do this when even a poor quality signal is better than no signal.