[Error] Error while creating a change set for stream

Hello,

I'm trying to create a change set:

IChangeSetHandle result = services.getScmService().createChangeSetForStream(workspaceHandle, component,changeSetComment, instruction, IScmService.DELTA_PER_INVOCATION, monitor);

The error :

    at com.ibm.team.repository.service.internal.db.jdbcwrappers.errlog.AbstractErrLogWrapper.logAndReturnException(AbstractErrLogWrapper.java:98)
    ... 147 more
Caused by: java.sql.SQLTransactionRollbackException: A lock could not be obtained within the time requested
    at org.apache.derby.impl.jdbc.SQLExceptionFactory40.getSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.Util.generateCsSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.TransactionResourceImpl.wrapInSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.TransactionResourceImpl.handleException(Unknown Source)
    at org.apache.derby.impl.jdbc.EmbedConnection.handleException(Unknown Source)
    at org.apache.derby.impl.jdbc.ConnectionChild.handleException(Unknown Source)
    at org.apache.derby.impl.jdbc.EmbedResultSet.closeOnTransactionError(Unknown Source)
    at org.apache.derby.impl.jdbc.EmbedResultSet.movePosition(Unknown Source)
    at org.apache.derby.impl.jdbc.EmbedResultSet.next(Unknown Source)
    at com.ibm.team.repository.service.internal.db.jdbcwrappers.stat.ResultSetStatWrapper.next(ResultSetStatWrapper.java:436)
    at com.ibm.team.repository.service.internal.db.jdbcwrappers.errlog.ResultSetErrLogWrapper.next(ResultSetErrLogWrapper.java:894)
    ... 145 more
Caused by: java.sql.SQLException: A lock could not be obtained within the time requested
    at org.apache.derby.impl.jdbc.SQLExceptionFactory.getSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.SQLExceptionFactory40.wrapArgsForTransportAcrossDRDA(Unknown Source)
    ... 156 more
Caused by: ERROR 40XL1: A lock could not be obtained within the time requested
    at org.apache.derby.iapi.error.StandardException.newException(Unknown Source)
    at org.apache.derby.impl.services.locks.ConcurrentLockSet.lockObject(Unknown Source)
    at org.apache.derby.impl.services.locks.AbstractPool.lockObject(Unknown Source)
    at org.apache.derby.impl.services.locks.ConcurrentPool.lockObject(Unknown Source)
    at org.apache.derby.impl.store.raw.xact.RowLocking3.lockRecordForRead(Unknown Source)
    at org.apache.derby.impl.store.access.conglomerate.OpenConglomerate.lockPositionForRead(Unknown Source)
    at org.apache.derby.impl.store.access.conglomerate.GenericScanController.fetchRows(Unknown Source)
    at org.apache.derby.impl.store.access.heap.HeapScan.fetchNext(Unknown Source)
    at org.apache.derby.impl.sql.execute.TableScanResultSet.getNextRowCore(Unknown Source)
    at org.apache.derby.impl.sql.execute.ProjectRestrictResultSet.getNextRowCore(Unknown Source)
    at org.apache.derby.impl.sql.execute.ProjectRestrictResultSet.getNextRowCore(Unknown Source)
    at org.apache.derby.impl.sql.execute.BasicNoPutResultSetImpl.getNextRow(Unknown Source)
    ... 149 more
com.ibm.team.repository.service.internal.UncheckedRepositoryException: com.ibm.team.repository.common.RetryableDatabaseException: CRJAZ1318E The server was unable to connect to the database. Retry the operation.
Transaction rollback

any guesses?

Thank you