You seem to embed asset using {{asset "helper.js"}} but there are multiple helper.js assets in your workspace.
You need to specify the asset using the relative "./helpers.js" or absolute "/folderx/helpers.js" path.

Not sure if the helper.js isn't created as sample by jsreport, this can be disabled using the following config

"extensions": { "sample-template": { "createSamples": false } }