Unexpected Error

The system encountered an error while processing the following request:
/en_US/default/search/results.displaypanel.displaycell.detailclick/ent:$002f$002fERC_235_449$002f0$002fOVERDRIVE:3e86b3ba-0046-45fc-b441-7e65dbaf2527/4/4/0

Error Summary

A component event handler method returned the value Block[Body of search/Results:displaypanel.displaycell.twilightzone, at classpath:com/sirsidynix/discovery/client/components/search/SearchDisplayCell.tml, line 212]. Return type org.apache.tapestry5.internal.structure.BlockImpl can not be handled.
Sun Feb 19 22:41:11 PST 2017