This issue occurs when a correct JDBC driver is not selected or if a two phase commit is enabled in the datasource. This can be corrected in the configuration file (eCMDataSource-*-jdbc.xml) under config/jdbc directory for the WebLogic domain set up.
1). Confirm that the driver name is as follows:
<driver-name>oracle.jdbc.OracleDriver</driver-name>
2). That OnePhaseSummit is enabled rather than TwoPhaseSummit as:
<global-transactions-protocol>OnePhaseCommit</global-transactions-protocol>
Find attached (Filename: change_eCMDataSource-8028-jdbc.xml) a sample file for reference.