TypeError: Cannot set property '3' of undefined

[eightsixeight]

015-10-06 12:17:08 [master] API died, spawning replacement... 2015-10-06 12:17:10 [pool](Thread 1) New block to mine at height 770528 w/ difficulty of 718962252 2015-10-06 12:17:10 [api] API started & listening on port 8117 2015-10-06 12:17:10 [api] Stat collection finished: 27 ms redis, 30 ms daemon 2015-10-06 12:17:10 [api] Broadcasting to 1 visitors and 0 address lookups

TypeError: Cannot set property '3' of undefined at collectStats as _onTimeout at Timer.listOnTimeout as ontimeout

2015-10-06 12:17:15 [master] API died, spawning replacement...

the line is the rediscommands line in

var windowTime = (((Date.now() / 1000) - config.api.hashrateWindow) | 0).toString(); redisCommands[0][3] = '(' + windowTime;