you are getting the following when using MySQL 4.x

2005-11-07 09:12:53,144 DEBUG [org.jboss.ejb.txtimer.GeneralPurposeDatabasePersistencePlugin] Executing DDL: create table TIMERS ( TIMERID varchar(80) not null, TARGETID varchar(80) not null, INITIALDATE TIMESTAMP not null, TIMERINTERVAL BIGINT, INSTANCEPK LONGBLOB, INFO LONGBLOB, constraint TIMERS_PK primary key (TIMERID,TARGETID))
2005-11-07 09:12:53,174 DEBUG [org.jboss.ejb.txtimer.DatabasePersistencePolicy] Starting failed jboss.ejb:service=EJBTimerService,persistencePolicy=database
java.sql.SQLException: Table 'TIMERS' already exists
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2926)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1571)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1666)
at com.mysql.jdbc.Connection.execSQL(Connection.java:2972)
at com.mysql.jdbc.Connection.execSQL(Connection.java:2902)
at com.mysql.jdbc.Statement.executeUpdate(Statement.java:929)

this is due to a bug in their jdbc driver v3.1.11

see the bug report for details
http://bugs.mysql.com/bug.php?id=14848


you'll see this problem happing as well with the table HILOSEQUENCES

2005-11-07 09:12:53,186 DEBUG [org.jboss.ejb.plugins.keygenerator.hilo.HiLoKeyGeneratorFactory] Executing DDL: create table HILOSEQUENCES (
SEQUENCENAME varchar(50) not null,
HIGHVALUES integer not null,
constraint hilo_pk primary key (SEQUENCENAME)
)
2005-11-07 09:12:53,187 DEBUG [org.jboss.ejb.plugins.keygenerator.hilo.HiLoKeyGeneratorFactory] Starting failed jboss:service=KeyGeneratorFactory,type=HiLo
java.sql.SQLException: Table 'HILOSEQUENCES' already exists