jboss mysql connection validation

Question

Hi,

when I put

<check-valid-connection-sql>select 1</check-valid-connection-sql>

in jboss datasourse config I get this exception:

java.lang.IllegalArgumentException: id to load is required for loading
org.hibernate.event.LoadEvent.<init>(LoadEvent.java:74)
org.hibernate.event.LoadEvent.<init>(LoadEvent.java:56)
org.hibernate.impl.SessionImpl.get(SessionImpl.java:839)
org.hibernate.impl.SessionImpl.get(SessionImpl.java:835)
org.hibernate.ejb.AbstractEntityManagerImpl.find(AbstractEntityManagerImpl.java:182)
org.jboss.seam.persistence.EntityManagerProxy.find(EntityManagerProxy.java:87)
com.klikmee.tc.providers.ProviderProxy.parseTransactionId(ProviderProxy.java:137)
com.klikmee.tc.providers.ProviderProxy.cancel(ProviderProxy.java:382)
com.klikmee.tc.providers.ProviderProxy.cancel(ProviderProxy.java:359)
com.klikmee.tc.servlets.DatecsTerminalCommunicatorServlet$RequestProcessor.processReverseTransaction(DatecsTerminalCommunicatorServlet.java:395)
com.klikmee.tc.servlets.DatecsTerminalCommunicatorServlet$RequestProcessor.process(DatecsTerminalCommunicatorServlet.java:123)
 com.klikmee.tc.servlets.DatecsTerminalCommunicatorServlet.doPost(DatecsTerminalCommunicatorServlet.java:808)
 com.klikmee.tc.servlets.DatecsTerminalCommunicatorServlet.doGet(DatecsTerminalCommunicatorServlet.java:862)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)

Tried to google it, but without success. What is this Illegal argument?