Workflow is not recognizing my custom fields

Hi all,

My workflow was working fine but recently I started to get errors.

For example, I have that rule :

rule Require Hours Worked

when State.changed {
  if (State == {Dev Complete}) {
    assert Hours Worked != null: "Error! You must assign a value first.";
  }
}

It is not recognizing Hours Worked. It is in my all projects, I know I have it and it was working fine so far.

This is the error I am getting :

Warning: Type t2 was not calculated
Error: No children in role "operation"(declared cardinality is 1)

Also in some fields I am getting "out of search scope" error.

Thanks