If you are using web services and are using visual stuido 2010, when you consume that service to be used in your application make sure the machine that it is being deployed to has .net framework 3.5 sp1. If it only has .net framework 3.5 that is not good enough. You will get an error like this
an error occurred while loading attribute ‘xmlserializerformatattribute’ on method blah blah blah
This error is basically telling you to install 3.5 sp1. Then the error will go away.
This happens because in vs2010 there are a few attributes that get added to web service proxies that are only usable when 3.5 sp1 is installed.