How to filter computer?

I am trying to get software per computer using the below relevance but it fails with an error “Singular expression refers to nonexistent object”.

The below query works to fetch all software for all assigned computers.

((name of computer of it, concatenation "|" of values of it) of results of properties of BES Fixlets whose (analysis flag of it and name of it = "Test")) 

If I change to below, it gives me error:

((name of computer whose (name of it = "Computer1") of it, concatenation "|" of values of it) of results of properties of BES Fixlets whose (analysis flag of it and name of it = "Test")) 

Thanks for providing me the fix;.

After lots of stupid experiments I realized that it is something with singularity. Changed code to below to work it fine.

names of computers

instead of

name of computer