the error: "org.neo4j.graphdb.NotInTransactionException"

The error message is somehing like this:

2014-01-25 16:37:43 ERROR HPAggregateProfile:141 - GRAMY_ERR:
org.neo4j.graphdb.NotInTransactionException
at org.neo4j.kernel.impl.index.IndexConnectionBroker.acquireResourceConnection(IndexConnectionBroker.java:49)
at org.neo4j.index.impl.lucene.LuceneIndex.getConnection(LuceneIndex.java:85)
at org.neo4j.index.impl.lucene.LuceneIndex.add(LuceneIndex.java:138)
at org.springframework.data.neo4j.support.typerepresentation.AbstractIndexingTypeRepresentationStrategy.add(AbstractIndexingTypeRepresentationStrategy.java:124)
at org.springframework.data.neo4j.support.typerepresentation.AbstractIndexingTypeRepresentationStrategy.addToTypesIndex(AbstractIndexingTypeRepresentationStrategy.java:116)
at org.springframework.data.neo4j.support.typerepresentation.AbstractIndexingTypeRepresentationStrategy.writeTypeTo(AbstractIndexingTypeRepresentationStrategy.java:59)
at org.springframework.data.neo4j.support.mapping.TRSTypeAliasAccessor.writeTypeTo(TRSTypeAliasAccessor.java:46)
at org.springframework.data.neo4j.support.mapping.TRSTypeAliasAccessor.writeTypeTo(TRSTypeAliasAccessor.java:26)

The solution is using transactions explicitly..
http://stackoverflow.com/questions/11485090/org-neo4j-graphdb-notintransactionexception

@Autowired
private GraphDatabaseService graphDb;

@Transactional
public void addRelation() {
  Transaction tx = graphDb.beginTx();
  ...
  tx.success(); //or tx.failure();
  tx.finish();
}

the error:"Referenced file contains errors (http://www.springframework.org/schema/beans/spring-beans-4.0.xsd)"

The error message is:

Referenced file contains errors (http://www.springframework.org/schema/beans/spring-beans-4.0.xsd).

A related link:  http://stackoverflow.com/questions/7267341/validation-error-of-spring-beans-schema-inside-application-context
In summary, the error may be resolved by doing the following:
" It was caused by some cached files. After removing those items (Preferences -> General -> Network Connections -> Cache) everything worked as expected. "
However, in my condition it was not helpful :( Another cause is using different versions together as stated:
"This error may have appeared because you had a mix of 2.5 xsd and 3.0 xsd in your applicationContext.xml. "
When i removed the version info from every element in xsi:schemaLocation, the project compiled successfully..