Error where node graph cannot be created with specific search

[taalbrecht]

searching for "ipp infection" from pubmed results in a node graph that cannot be created as the source data for the graph it is missing proper columns for Node and Edge for some reason. The error displayed on the webpage where the node graph should be is as follows:

ERROR: edgeData must have 'source' and 'target' columns

[taalbrecht]

also occurs with search for "cell fusion cancer metastasis in vivo"