LINQ insert method problem, .NET 3.5, VS2008, LINQ

Overview
I have a form that the user fills in.
A event to my C# codebehind page fires on the save button click.
The btnSave_Click method load up the 3 LINQ Entities with the correct values.
I call the LINQ method "InsertProject" to insert the data into the SQL tables.

The error message I am getting is "The type arguments for method BLAH cannot be inferred from the usage. Try specifying the type arguments explicity.

This is my method

public static Project InsertProject(Security securityAccess, Proj project, Property property)
{
    DevDataContext db = new DevDataContext();
    db.Security.InsertOnSubmit(securityAccess);
    db.SubmitChanges();

    project.ControlID = securityAccess.ControlID;
    db.Proj.InsertOnSubmit(project);
    db.SubmitChanges();

    projectProperty.ProjectID = project.ProjectID;
    db.Property.InsertAllOnSubmit(projectProperty);   <=== ERROR HERE

    db.SubmitChanges();
    return project;
}