I'm fairly perplexed by this issue.. 

I have a form Called Task

  This has a field called TestLook which is a Lookup of a form called Contractor. The lookup field is Token_Secret.

I have checked and there is definitely a record in Task that has TestLook set to a Contractor record that has the value for Token_Secret match input.Token, I am trying like this in my page:

tasks = Task [TestLook.Token_Secret = input.Token];

Is the way I am doing the fetch not correct? I'm perplexed as everything seems to line up, when I try this in my page I get:

Error details: Error in executing Contractor_Update_Page 'tasks' is an empty set and values cannot be retrieved (21)