Failed to apply web.config modifications to file 'C:\inetpub\wwwroot\wss\VirtualDirectories\9675\web.config'

Hi

We're using Sharepoint 2010 trying to install a second Web Front end server. The first one went through the sharepoint configuartion wizard fine, however the when i go to do the second one it throws up the following error:

Failed to apply web.config modifications to file 'C:\inetpub\wwwroot\wss\VirtualDirectories\9675\web.config'. Failed to apply a web.config modification to file 'C:\inetpub\wwwroot\wss\VirtualDirectories\9675\web.config'.

The specified node "configuration/system.webserver/httpprotocol/customheaders" was not found in the web.config file

There are two app servers (load balanced) and so far one web front end server.

Thanks