The convert jobs alway pending. Please help?

I just see only error from /opt/kaltura/log/batch/partnerloadcleanup-0-2016-08-18.err.log

PHP Fatal error:  Uncaught exception 'KalturaClientException' with message 'failed to unserialize server result
' in /opt/kaltura/app/batch/client/KalturaClientBase.php:401
Stack trace:
#0 /opt/kaltura/app/batch/client/KalturaClient.php(1122): KalturaClientBase->doQueue()
#1 /opt/kaltura/app/batch/batches/Cleanup/KAsyncPartnerLoadCleanup.class.php(28): KalturaBatchService->updatePartnerLoadTable()
#2 /opt/kaltura/app/batch/batches/Cleanup/KAsyncPartnerLoadCleanupExe.php(11): KAsyncPartnerLoadCleanup->run()
#3 {main}
  thrown in /opt/kaltura/app/batch/client/KalturaClientBase.php on line 401

And I also check /opt/kaltura/log/batch//convert-0-2016-08-18.log But it alway returned 0 sent to scheduler

2016-08-19 11:29:37 [0.000099] [1210349954] [12] [BATCH] [KalturaClientBase->doQueue] NOTICE: execution time for [https://front1.com/api_v3/service/batch/action/getExclusiveJobs]: [0.16400408744812]
2016-08-19 11:29:37 [0.000104] [1210349954] [13] [BATCH] [KJobHandlerWorker->run] INFO: 0 jobs to handle
2016-08-19 11:29:37 [0.000073] [1210349954] [14] [BATCH] [KJobHandlerWorker->run] INFO: Queue size: 0 sent to scheduler
2016-08-19 11:29:37 [0.000220] [1210349954] [15] [BATCH] [KalturaClientBase->doQueue] NOTICE: service url: [https://front1.2501pf.com]
2016-08-19 11:29:37 [0.000199] [1210349954] [16] [BATCH] [KalturaClientBase->doCurl] NOTICE: curl: https://front1.com/api_v3/service/batch/action/getQueueSize
2016-08-19 11:29:37 [0.000080] [1210349954] [17] [BATCH] [KalturaClientBase->doCurl] NOTICE: post: {"format":"3","ignoreNull":true,"clientTag":"batch: BATCH1 KAsyncConvert index: 0 sessionId: 1210349954","apiVersion":"3.3.0","workerQueueFilter":{"objectType":"KalturaWorkerQueueFilter","schedulerId":"88957","workerId":"70","jobType":"0","filter":{"objectType":"KalturaBatchJobFilter","jobTypeEqual":"0","jobSubTypeIn":"1,2,99,3,fastStart.FastStart,segmenter.Segmenter,mp4box.Mp4box,vlc.Vlc,document.ImageMagick,201,202,quickTimeTools.QuickTimeTools"}},"partnerId":"-1","ks":"ZTZhYTliNDYxOWY2ODllNWMwZGU2NGIzMGIxNjZjNjA1NGUzYzc4NnwtMTs7MTQ3NDE2NTc3NzsyOzE0NzE1NzM3NzcuNTk7YmF0Y2hVc2VyO2Rpc2FibGVlbnRpdGxlbWVudDstMTs=","kalsig":"8e751475aa15cfe44d04ac44c20312c0"}
2016-08-19 11:29:37 [0.039682] [1210349954] [18] [BATCH] [KalturaClientBase->doQueue] NOTICE: server: [front1.com], session: [1074452967]
2016-08-19 11:29:37 [0.000120] [1210349954] [19] [BATCH] [KalturaClientBase->doQueue] NOTICE: result (serialized): i:240;
2016-08-19 11:29:37 [0.000122] [1210349954] [20] [BATCH] [KalturaClientBase->doQueue] NOTICE: result (object dump): 240
2016-08-19 11:29:37 [0.000096] [1210349954] [21] [BATCH] [KalturaClientBase->doQueue] NOTICE: execution time for [https://front1.com/api_v3/service/batch/action/getQueueSize]: [0.040301084518433]
2016-08-19 11:29:37 [0.000244] [1210349954] [22] [BATCH] [KBatchBase->done] INFO: Done after [0.24942278862] seconds

Any help?