SQL error (HSQL) on upgrade task

2011-09-05 12:22:23,443 ERROR [2-UpgradeTaskBackgroundThread:pool-8-thread-1] [AbstractStatementUpgradeTask] Unable to run ALTER TABLE USER_COMMIT DROP COLUMN BUILDRESULTSUMMARY_ID : Column is referenced in constraint or view: FKF8936C2BA958B29F in statement [ALTER TABLE USER_COMMIT DROP COLUMN BUILDRESULTSUMMARY_ID]
java.sql.SQLException: Column is referenced in constraint or view: FKF8936C2BA958B29F in statement [ALTER TABLE USER_COMMIT DROP COLUMN BUILDRESULTSUMMARY_ID]
	at org.hsqldb.jdbc.Util.sqlException(Unknown Source)
	at org.hsqldb.jdbc.jdbcStatement.fetchResult(Unknown Source)
	at org.hsqldb.jdbc.jdbcStatement.execute(Unknown Source)
	at com.mchange.v2.c3p0.impl.NewProxyStatement.execute(NewProxyStatement.java:1006)
	at com.atlassian.bamboo.upgrade.tasks.AbstractStatementUpgradeTask.doUpgrade(AbstractStatementUpgradeTask.java:42)
	at com.atlassian.bamboo.upgrade.tasks.AbstractInHibernateTransactionUpgradeTask$1.doInHibernateTransaction(AbstractInHibernateTransactionUpgradeTask.java:40)
	at com.atlassian.bamboo.persistence.BambooConnectionTemplate$1$1.doInHibernate(BambooConnectionTemplate.java:51)
	at org.springframework.orm.hibernate.HibernateTemplate.execute(HibernateTemplate.java:370)
	at com.atlassian.bamboo.persistence.BambooConnectionTemplate$1.doInTransactionWithoutResult(BambooConnectionTemplate.java:44)
	at org.springframework.transaction.support.TransactionCallbackWithoutResult.doInTransaction(TransactionCallbackWithoutResult.java:33)
	at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:127)
	at com.atlassian.bamboo.persistence.BambooConnectionTemplate.execute(BambooConnectionTemplate.java:39)
	at com.atlassian.bamboo.upgrade.tasks.AbstractInHibernateTransactionUpgradeTask.doUpgrade(AbstractInHibernateTransactionUpgradeTask.java:36)
	at com.atlassian.bamboo.upgrade.AbstractUpgradeManager.runUpgradeTask(AbstractUpgradeManager.java:175)
	at com.atlassian.bamboo.upgrade.UpgradeManagerImpl.doUpgrade(UpgradeManagerImpl.java:92)
	at com.atlassian.bamboo.upgrade.UpgradeLauncher$1.call(UpgradeLauncher.java:115)
	at com.atlassian.bamboo.upgrade.UpgradeLauncher$1.call(UpgradeLauncher.java:112)
	at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
	at java.util.concurrent.FutureTask.run(FutureTask.java:138)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
	at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
	at java.util.concurrent.FutureTask.run(FutureTask.java:138)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
	at com.atlassian.bamboo.build.pipeline.concurrent.NamedThreadFactory$2.run(NamedThreadFactory.java:50)
	at java.lang.Thread.run(Thread.java:619)