Specify search on property

I have an ItemType named "Document" that has a property called "project".  The project property is itself an item that has an ItemType as its data source.  I attempt to set an Item below and specify the search term I want which is "FCF".  All I get is an error saying "Not a single Item" and I cannot figure out what I have wrong.  Any help greatly appreciated!

Item query = this.newItem("ThisProject", "get");

query.setProperty("project_name", "FCF");

query = query.apply();

this.setProperty("project", query.getProperty("project_name"));

this.setPropertyCondition("project","in");

return this;