I've seen one or two posts concerning issues with this driver, but none have addressed the issue I'm having. Here is my datasource XML:

<?xml version="1.0" encoding="UTF-8"?>

<!-- The SQL Server 2005 Database JCA connection factory config $Id: sql2005jdbc-ds.xml,v 1.0 2005/10/7 mattn Exp $ -->

<datasources>

 <!-- Non-transactional datasource (uses no transactions) -->
 <no-tx-datasource>

 <!-- The jndi name of the DataSource, it is prefixed with java:/ -->
 <!-- Datasources are not available outside the virtual machine -->
 <jndi-name>OnBoard</jndi-name>

 <!-- The connection url -->
 <connection-url>jdbc:sqlserver://localhost:1433;databaseName=OnBoard</connection-url>

 <!-- The driver class -->
 <driver-class>com.microsoft.sqlserver.jdbc.SQLServerDriver</driver-class>

 <!-- The login and password -->
 <user-name>aaa</user-name>
 <password>bbb</password>

 <!-- This will be run before a managed connection is removed from the pool for use by a client
 <check-valid-connection-sql>select 1</check-valid-connection-sql>-->

 <!-- The minimum connections in a pool/sub-pool. Pools are lazily
 constructed on first use -->
 <min-pool-size>10</min-pool-size>

 <!-- The maximum connections in a pool/sub-pool -->
 <max-pool-size>2000</max-pool-size>

 <!-- metadata for datasource type -->
 <metadata>
 <type-mapping>MS SQLSERVER2000</type-mapping>
 </metadata>

 </no-tx-datasource>

 <!-- Local transaction datasource (uses no transactions) -->
 <local-tx-datasource>

 <!-- The jndi name of the DataSource, it is prefixed with java:/ -->
 <!-- Datasources are not available outside the virtual machine -->
 <jndi-name>TXOnBoard</jndi-name>

 <!-- The connection url -->
 <connection-url>jdbc:sqlserver://localhost:1433;databaseName=OnBoard</connection-url>

 <!-- The driver class -->
 <driver-class>com.microsoft.sqlserver.jdbc.SQLServerDriver</driver-class>

 <!-- The login and password -->
 <user-name>aaa</user-name>
 <password>bbb</password>

 <!-- This will be run before a managed connection is removed from the pool for use by a client
 <check-valid-connection-sql>select 1</check-valid-connection-sql>-->

 <!-- The minimum connections in a pool/sub-pool. Pools are lazily
 constructed on first use -->
 <min-pool-size>10</min-pool-size>

 <!-- The maximum connections in a pool/sub-pool -->
 <max-pool-size>2000</max-pool-size>

 <!-- metadata for datasource type -->
 <metadata>
 <type-mapping>MS SQLSERVER2000</type-mapping>
 </metadata>

 </local-tx-datasource>
</datasources>

2006-04-04 16:52:29,714 WARN [org.jboss.tm.TransactionImpl] XAException: tx=TransactionImpl:XidImpl[FormatId=257, GlobalId=ws-lumpkin/1, BranchQual=, localId=1] errorCode=XA_UNKNOWN(0)
org.jboss.resource.connectionmanager.JBossLocalXAException: could not commit local tx; - nested throwable: (org.jboss.resource.JBossResourceException: SQLException; - nested throwable: (com.microsoft.sqlserver.jdbc.SQLServerException: The COMMIT TRANSACTION request has no corresponding BEGIN TRANSACTION.))
at org.jboss.resource.connectionmanager.TxConnectionManager$LocalXAResource.commit(TxConnectionManager.java:702)
at org.jboss.tm.TransactionImpl$Resource.commit(TransactionImpl.java:2141)
at org.jboss.tm.TransactionImpl.commitResources(TransactionImpl.java:1674)
at org.jboss.tm.TransactionImpl.commit(TransactionImpl.java:312)
at org.jboss.tm.TxManager.commit(TxManager.java:200)