Nested tables with ajax service - oSettings is null

I'm trying to build a table that has expandable/collapsible rows. When expanded, the detail is another table. Both the main table and the detail tables are populated from ajax services.

I've tried to follow the various examples that I've found, but when I expand a row, I see the following in the error console:

Error: TypeError: oSettings is null
Source File: ...jquery.dataTables.js Line 6094

I've put the page up so that you can see it break. Go to url: http://www.broadinstitute.org/gtex?page=newSearchEqtls
In the "Browse Significant eQTLs" box, select a tissue -- e.g., Adipose Subcutaneous. Hit the "Significant eQTLs" button. Then you will see the table. Click on the + image and you will get the error.

I'm sure there is something basic that I'm missing, but at this point I'm stuck.

Thanks, Jared Nedzel