C# linq

Question

I am trying to write a linq to sql statement in a C# 2008 application that writes to a sql server 2008 database.

I am able to write the following statement where there are no syntax errors;

var fdrPkg = (from a in rData.ails where a.PID == S).


However the above editor will not let me write the select part of the statement where I add firstordefault.

Thus can you tell me what you think could be wrong and/or how I can change the linq to sql statement so that it will work for me?