[EMBOSS] specify primer3 directory?

[Paul Tanger]

Hi,
I have a local install of emboss and I'm trying to get eprimer3 to
work, but I'm getting this error:

"Error: thermodynamic approach chosen, but path to thermodynamic
parameters not specified"

primer3 is installed, but not in the default location (which I think
is /opt/primer3_config ?) .
How do I specify where primer3 is installed?  Or is the cause of this
error something else?

googled for an answer for a while, but couldn't find one.

Thanks!