I am able to get the name of the computer and its id. My report has two text boxes that the user enters the hostname for two different machines to compare configurations of. I lookup the hostname to get the id of the computers. And then use the id in this expression
(name of it, last report time of it, operating system of it, cpu of it, value of result from (bes property "RAM") of it, value of result from (bes property "Hardware Model") of it, value of result from (bes property "System Manufacturer") of it, value of result from (bes property "Default_Java") of it) of bes computer <computer id>
This expression evaluates just fine after I click the preview button, but not on the initial load of the page.