IMAP connection fails with Exception

[S.F.]

I'm having a rather weird problem with a fresh install of Zimbra Open Source: It all works fine except for IMAP connections; login succeeds but then I get this in the log:

WARN  [ScheduledTask-StatsDumper-1] [] scheduler - Exception during execution of task mailboxd.csv
java.lang.IllegalArgumentException: committed = 67174400 should be < max = 67108864
        at java.lang.management.MemoryUsage.<init>(MemoryUsage.java:145)
        at sun.management.MemoryPoolImpl.getUsage0(Native Method)
        at sun.management.MemoryPoolImpl.getUsage(MemoryPoolImpl.java:78)
        at com.zimbra.cs.util.MemoryStats.getStatData(MemoryStats.java:294)
        at com.zimbra.common.stats.RealtimeStats.getData(RealtimeStats.java:69)
        at com.zimbra.cs.stats.ZimbraPerf$MailboxdStats.getDataLines(ZimbraPerf.java:272)
        at com.zimbra.common.stats.StatsDumper.call(StatsDumper.java:98)
        at com.zimbra.common.stats.StatsDumper.call(StatsDumper.java:42)
        at com.zimbra.common.util.TaskScheduler$TaskRunner.call(TaskScheduler.java:98)
        at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:269)
        at java.util.concurrent.FutureTask.run(FutureTask.java:123)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:65)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:168)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:650)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:675)
        at java.lang.Thread.run(Thread.java:595)

The IMAP client (Outlook in this case) will timeout after a while. This happens both with and without SSL. Any ideas?

Zimbra 5.0.10 on Ubuntu 8.04.

[garyo]

I'm getting the same tracebacks in my mailbox.log, though I don't think it's related to any IMAP timeouts. Anyone know what's going on here?