Particular user cannot be found from JIRA running with Crowd

2007-08-15 23:35:26,271 JiraQuartzScheduler_Worker-1 ERROR [service.util.handler.CreateIssueHandler] Could not create issue!
java.lang.NullPointerException
        at com.opensymphony.user.User.<init>(User.java:53)
        at com.opensymphony.user.UserManager.buildEntity(UserManager.java:339)
        at com.opensymphony.user.UserManager.getEntities(UserManager.java:290)
        at com.opensymphony.user.UserManager.getUsers(UserManager.java:200)
        at com.atlassian.core.user.UserUtils.getAllUsers(UserUtils.java:65)
        at com.atlassian.jira.service.util.handler.AbstractMessageHandler.findUserByEmail(AbstractMessageHandler.java:539)
        at com.atlassian.jira.service.util.handler.AbstractMessageHandler.getAuthorFromSender(AbstractMessageHandler.java:493)
        at com.atlassian.jira.service.util.handler.AbstractMessageHandler.getReporter(AbstractMessageHandler.java:460)
        at com.atlassian.jira.service.util.handler.CreateIssueHandler.handleMessage(CreateIssueHandler.java:91)
        at com.atlassian.jira.service.util.handler.CreateOrCommentHandler.handleMessage(CreateOrCommentHandler.java:115)
        at com.atlassian.jira.service.services.mail.MailFetcherService.run(MailFetcherService.java:190)
        at com.atlassian.jira.service.JiraServiceContainerImpl.run(JiraServiceContainerImpl.java:67)
        at com.atlassian.jira.service.ServiceRunner.execute(ServiceRunner.java:61)
        at org.quartz.core.JobRunShell.run(JobRunShell.java:191)
        at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:516)
2007-08-15 23:35:26,312 JiraQuartzScheduler_Worker-1 ERROR [crowd.integration.osuser.CrowdCredentialsProvider] Failed to find user: tlahtela