Issue while upgrading Jasperser from 4.5 to 5.1

We are using the community version of JasperServer 4.5.0.

Currently we are in the process of upgrading the JasperServer to 5.1 While performing the upgrade i am getting the following error.

[java] Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Table 'jasperserver.jivirtualdatasource' doesn't exist

[java] at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

[java] at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)

[java] at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)

[java] at java.lang.reflect.Constructor.newInstance(Constructor.java:513)

[java] at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)

[java] at com.mysql.jdbc.Util.getInstance(Util.java:381)

[java] at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1030)

[java] at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)

[java] at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3558)

[java] at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3490)

[java] at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1959)

[java] at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2109)

[java] at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2648)

[java] at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2077)

[java] at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:2228)

[java] at org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:92)

[java] at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:208)

[java] at org.hibernate.loader.Loader.getResultSet(Loader.java:1812)

[java] at org.hibernate.loader.Loader.doQuery(Loader.java:697)

[java] at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259)

[java] at org.hibernate.loader.Loader.doList(Loader.java:2232)

I am using js-upgrade-samedb-ce.sh for the upgrade and when run in the test mode the test is successful.

Any reason the upgrade is failing?