TypeError: Cannot read property 'join' of undefined

[gcsfred]

What causes this problem?

C:\Users\Gustavo>jilla ls
C:\Users\Gustavo\AppData\Roaming\npm\node_modules\jilla\bin\jilla:141
res.body.errorMessages.join('\n')
^

TypeError: Cannot read property 'join' of undefined
at C:\Users\Gustavo\AppData\Roaming\npm\node_modules\jilla\bin\jilla:141:31
at Request.callback (C:\Users\Gustavo\AppData\Roaming\npm\node_modules\jilla
\node_modules\superagent\lib\node\index.js:630:3)
at Request. (C:\Users\Gustavo\AppData\Roaming\npm\node_modules\ji
lla\node_modules\superagent\lib\node\index.js:131:10)
at emitOne (events.js:77:13)
at Request.emit (events.js:169:7)
at IncomingMessage. (C:\Users\Gustavo\AppData\Roaming\npm\node_mo
dules\jilla\node_modules\superagent\lib\node\index.js:773:12)
at emitNone (events.js:72:20)
at IncomingMessage.emit (events.js:166:7)
at endReadableNT (_stream_readable.js:893:12)
at doNTCallback2 (node.js:429:9)

C:\Users\Gustavo>jilla
usage: jilla []

Commands:
config Update jilla configuration
ls List open issues
start Start working on an issue
stop (--log) Stop working on an issue (and log time)
log Log work
running List issues in progress
resolve Resolve issue
reopen Reopen issue
close Close issue
needinfo Set issue status to Needs Info
status (status) Changes issue status to "status" (no status to ge
t a list of options)
search Find issues
describe Display issue synopsis
comments (--reverse) Display comments on an issue
subtasks List an issue's subtasks
comment "" Comment on an issue
user Search for a user
assign Assign issue to a user

C:\Users\Gustavo>