Build Agent keeps restarting after failed upgrade request from server

Please take a look at upgrade.log - there can be a reason why agent can't upgrade properly, or attach this log here.

It's rather big, I've cut off what's going after error.

I think that is interesting:
-----------------------------------------------------------------------------------------
[2009-12-09 15:47:20,318]   INFO - buildServer.agent.LauncherUtil - Unpacking /home/teamcity/TeamCity/buildAgent/plugins/idea_dist.jar: 11197440 bytes
[2009-12-09 15:47:20,348]  ERROR - ver.agent.upgrade.AgentUpgrade - Upgrade failed :error in opening zip file
java.util.zip.ZipException: error in opening zip file
    at java.util.zip.ZipFile.open(Native Method)
    at java.util.zip.ZipFile.<init>(ZipFile.java:114)
    at java.util.zip.ZipFile.<init>(ZipFile.java:131)
    at jetbrains.buildServer.agent.LauncherUtil.unzip(LauncherUtil.java:98)
    at jetbrains.buildServer.agent.upgrade.UnzipUpgradeFolder.extractAll(UnzipUpgradeFolder.java:33)
    at jetbrains.buildServer.agent.upgrade.UnzipUpgradeFolder.doUpgrade(UnzipUpgradeFolder.java:25)
    at jetbrains.buildServer.agent.upgrade.UpgradeFolder.upgrade(UpgradeFolder.java:36)
    at jetbrains.buildServer.agent.upgrade.AgentUpgrade.doUpgrade(AgentUpgrade.java:83)
    at jetbrains.buildServer.agent.upgrade.AgentUpgrade.applyUpdates(AgentUpgrade.java:55)
    at jetbrains.buildServer.agent.upgrade.UpgradeRunBase.run(UpgradeRunBase.java:32)
    at jetbrains.buildServer.agent.upgrade.UpgradeMode$4.run(UpgradeMode.java:48)
    at jetbrains.buildServer.agent.upgrade.Upgrade2.main2(Upgrade2.java:33)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at jetbrains.buildServer.agent.ClazzLoader.call(ClazzLoader.java:59)
    at jetbrains.buildServer.agent.ClazzLoader.callMain2(ClazzLoader.java:19)
    at jetbrains.buildServer.agent.upgrade.Upgrade.main(Upgrade.java:16)
[2009-12-09 15:47:20,353]   INFO - ver.agent.upgrade.AgentUpgrade - AGENT UPDATE FAILED, exiting ...
----------------------------------------------------------------------------------------

Is there something wrong with /home/teamcity/TeamCity/buildAgent/plugins/idea_dist.jar? I don't really need integration with IDEA, can I skip it?

Thanks!

It seems the file idea_dist.jar is broken on agent. I would recommend to reinstall agent.

Agent is the same box as the server. It's strange, 'cause
./webapps/ROOT/update/plugins/idea_dist.jar on the server had -rw------- attributes, while other files are -rw-r--r--

Also, I cannot open this file with Archive Manager under gnome

Please try to extract this file from the distribution again.