hey i work for a broadband company the reason sky cant activate new broadband for you is they do need an active BT line this means that you will have to go to bt and ask them to insert a line that will cost you £125 connection charge and you will then be incontract with bt for at least 12months

the only other way round it is if you go to a cable company like virgin who do not provide the braodband through a bt line but if your heart is set on sky then unfortunately you will have to go through the route of BT and pay the connection charge

your other alterantive is to ask talk talk for a new wireless router or go through the tech support with them and they should be able to resolve your issue

hope this helps you