I know that if I want to have clickable hyperlinks for citations, I need 
to turn off 'compress' for the citation type:

\setupcite[authoryears][compress=no]

The problem is that this doesn't seem to work: I get an 'unknown 
reference' error.

references      : unknown reference [][Balachandran2008
references      : unknown reference [][Balachandran2008
references      : unknown reference [][Balachandran2008

Strangely, this only happens when I want to refer to multiple authors, 
e.g. \cite[ref1, ref2, ref3], and everything works fine if I just do 
\cite[ref1].

I've attached a minimal example. Where am I going wrong?

-- 
Michael Murphy