Error while importing Bamboo buildresults from bdac due to missing authors from commits

2008-03-31 14:57:15,701 ERROR [btpool0-1] [ImportExportManagerImpl] Exception occurred during import
java.lang.NumberFormatException: For input string: ""
	at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)
	at java.lang.Long.parseLong(Long.java:424)
	at java.lang.Long.parseLong(Long.java:461)
	at com.atlassian.bamboo.migration.ProjectMapper.importBuildResultCommits(ProjectMapper.java:683)
	at com.atlassian.bamboo.migration.ProjectMapper.importBuildResultSummaries(ProjectMapper.java:630)
	at com.atlassian.bamboo.migration.ProjectMapper.importBuilds(ProjectMapper.java:552)
	at com.atlassian.bamboo.migration.ProjectMapper.importXml(ProjectMapper.java:498)
	at com.atlassian.bamboo.migration.XmlMigrator.importXml(XmlMigrator.java:169)
	at com.atlassian.bamboo.migration.XmlMigrator$$FastClassByCGLIB$$b6578fc7.invoke(<generated>)
	at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:149)
	at org.springframework.aop.framework.Cglib2AopProxy$CglibMethodInvocation.invokeJoinpoint(Cglib2AopProxy.java:694)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)
	at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
	at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:629)
	at com.atlassian.bamboo.migration.XmlMigrator$$EnhancerByCGLIB$$7730bcae.importXml(<generated>)
	at com.atlassian.bamboo.migration.ImportExportManagerImpl$2.call(ImportExportManagerImpl.java:97)
	at com.atlassian.bamboo.migration.ImportExportManagerImpl$2.call(ImportExportManagerImpl.java:86)
	at com.atlassian.bamboo.buildqueue.manager.LocalAgentManagerImpl.executeIfIdle(LocalAgentManagerImpl.java:342)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)