Error during backup

I appreciate your help regarding a fix for the following error message which appears on performing backup by manual and can't backup data by schedule. The current version is 9121.

ERROR DETAIL:

Starting....
Jan 29, 2016 12:03:58 PM com.adventnet.servicedesk.server.utils.SDDataManager setStandAlone
INFO: Going to set the standAlone param as : true
Jan 29, 2016 12:03:58 PM com.adventnet.servicedesk.server.utils.SDDataManager setStandAlone
INFO: Going to reset rootDir using server.dir
Jan 29, 2016 12:03:58 PM com.adventnet.servicedesk.server.utils.SDDataManager <init>
INFO: rootDir :: ..
Jan 29, 2016 12:03:58 PM com.adventnet.servicedesk.server.utils.SDDataManager <init>
INFO: netutilsData :: {RELEASE={version=9.1}, BUILD={number=9121}}
Jan 29, 2016 12:03:58 PM com.adventnet.servicedesk.server.utils.SDDataManager <init>
INFO: rebrandData :: {ADSELFSERVICE={name=ADSelfService Plus}, OPMANAGER={name=OpManager}, PRODUCT={name=ManageEngine ServiceDesk Plus}, ADMANAGER={name=ADManager Plus}}Active DB Server = mysql
Database connectionProp : useUnicode=true
characterEncoding=UTF-8

Error while trying to instantiate SQLGeneratir com.adventnet.db.adapter.SQLGener
ator java.lang.InstantiationException: com.adventnet.db.adapter.SQLGenerator
Database started
*************************************************************
Number of tables found : 1359
-------------------------------------------------------------
Build number : 9121
-------------------------------------------------------------
backup_info.xml : true
-------------------------------------------------------------
Ignored Table List
-------------------------------------------------------------
AaaAccSessionAudit
AaaAccHttpSession
AaaAccSessionProp
AaaAccSession
AuditRecord
OperationAuditRecord
AuditResultProperty
AuditResourceProp
AuditOperProperty
RecentItems
-------------------------------------------------------------
Going to take full backup with file attachments
-------------------------------------------------------------
deleting duplicate entries in WordMap table : 0
*************************************************************

Please wait ! backup in Progress...................
0-----------------------50------------------------100(%)
====================================ERROR = *Base table or view not found, mess
age from server: "Table 'servicedesk.arc_workordertoresource' doesn't exist"* Qu
ery = SELECT max(WORKORDERID) FROM Arc_WorkOrderToResource
java.lang.Exception: Unable to get the data from [Arc_WorkOrderToResource] table

        at com.adventnet.servicedesk.tools.SDBackUp.dumpTableUsingLimit(SDBackUp
.java:1485)
        at com.adventnet.servicedesk.tools.SDBackUp.dumpTableUsingLimit(SDBackUp
.java:1506)
        at com.adventnet.servicedesk.tools.SDBackUp.dumpTableUsingCriteria(SDBac
kUp.java:1125)
        at com.adventnet.servicedesk.tools.SDBackUp.dumpTable(SDBackUp.java:1096
)
        at com.adventnet.servicedesk.tools.SDBackUp.startBackup(SDBackUp.java:36
9)
        at com.adventnet.servicedesk.tools.SDBackUp.process(SDBackUp.java:104)
        at com.adventnet.servicedesk.tools.SDBackUp.main(SDBackUp.java:2425)

stopping DB Server >>>>> false
java.lang.Exception: Unable to get the data from [Arc_WorkOrderToResource] table