BTC-RPC-EXPLORER mixins.pug error when trying to explore a block

I have btc-rpc-explorer running in Ubuntu. When I try to explore a selected Bitcoin block in the rpc explorer, I get the following error message:

TypeError: /usr/local/lib/node_modules/btc-rpc-explorer/views/includes/shared-mixins.pug:227

227 if (!coinbaseTx && Object.keys(txInputs).length < tx.vin.length)

Cannot convert undefined or null to object

Any suggestions on what is wrong with the code in line 227? Thanks

I have tried Googling for the answer but I'm not sure of the correct answer in my case, and I'm a noobie.