Windchill M030 stopped suddenly to publish anything to our MES system

Please help me as Windchill M030 has stopped suddenly to publish anything to our MES system.

It is not able to create XML file for part/plan/etc we publish from Windchill.

There is error available at method server after publish but i can't get it understand that what's the problem with Windchill happened.

error is:

2018-03-28 11:57:55,200 INFO [WfUserWorkQueue.PoolQueueThread-2] wt.system.out Administrator - ESI release : ESI ( 600 ) : Continues to publish "SPART_032801, SPART_032801, A.1 (Manufacturing)".
2018-03-28 11:57:56,042 INFO [SessionThread-4] wt.system.out - Debug: Start Custom CodeDebug: Generate ResponseDebug: Writing IeCollection to file: nullERROR: PublishToSolumina method failed: null
2018-03-28 11:57:56,042 INFO [SessionThread-4] wt.system.err - java.lang.NullPointerException
2018-03-28 11:57:56,042 INFO [SessionThread-4] wt.system.err - 	at java.io.FileOutputStream.<init>(FileOutputStream.java:203)
2018-03-28 11:57:56,042 INFO [SessionThread-4] wt.system.err - 	at java.io.FileOutputStream.<init>(FileOutputStream.java:101)
2018-03-28 11:57:56,042 INFO [SessionThread-4] wt.system.err - 	at com.infoengine.compiledTasks.file.C$3a$5cptc$5cWindchill$5cWindchill$5ctasks.com.ptc.windchill.esi.export.exporttosolumina$2exml.invoke(exporttosolumina$2exml.java:145)
2018-03-28 11:57:56,042 INFO [SessionThread-4] wt.system.err - 	at com.infoengine.SAK.Task.invoke(Task.java:1806)
2018-03-28 11:57:56,042 INFO [SessionThread-4] wt.system.err - 	at com.infoengine.SAK.Task.invoke(Task.java:1714)
2018-03-28 11:57:56,042 INFO [SessionThread-4] wt.system.err - 	at com.ptc.windchill.esi.txn.ESIResponseSender.run(ESIResponseSender.java:149)
2018-03-28 11:57:56,042 INFO [SessionThread-4] wt.system.err - 	at wt.session.SessionThread.run(SessionThread.java:225)
2018-03-28 11:57:56,089 ERROR [SessionThread-4] tasks.com.ptc.windchill.esi.export.ExportToFile - Error while executing the Write-To-File webject.
(com.infoengine.util.IEResource/9) com.infoengine.exception.fatal.IEInternalServiceException: Error trying to invoke webject: "Write-To-File". Nested exception is: 
java.lang.NullPointerException
	at com.infoengine.procunit.webject.WebjectProcessor.invokeWebject(WebjectProcessor.java:661)
	at com.infoengine.procunit.webject.WebjectProcessor.processTask(WebjectProcessor.java:210)
	at com.infoengine.SAK.Webject.invoke(Webject.java:491)
	at com.infoengine.SAK.ExternalWebject.invoke(ExternalWebject.java:119)
	at com.infoengine.compiledTasks.file.C$3a$5cptc$5cWindchill$5cWindchill$5ctasks.com.ptc.windchill.esi.export.exporttosolumina$2exml.invoke(exporttosolumina$2exml.java:236)
	at com.infoengine.SAK.Task.invoke(Task.java:1806)
	at com.infoengine.SAK.Task.invoke(Task.java:1714)
	at com.ptc.windchill.esi.txn.ESIResponseSender.run(ESIResponseSender.java:149)
	at wt.session.SessionThread.run(SessionThread.java:225)
Caused by: java.lang.NullPointerException
	at com.ptc.windchill.esi.lite.tgt.webject.WriteToFile.writeToFile(WriteToFile.java:140)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at com.infoengine.procunit.webject.WebjectProcessor.invokeWebject(WebjectProcessor.java:573)

Also come to know that .SAV file is not being created in C:\PTC directory but previously it was successfully created after publishing anything.

Please help me as soon as possible as it stopped us to work further.