The story:

1. Hudson Slave process is running
2. Someone or something deletes slave's Remote FS root directory
3. Hudson reports ZipException with message: "error reading zip file"

I would like the message to be improved to something more obvious, like "Slave JAR files are missing. It appears they were deleted."

In our case the problem (although now seems obvious) was hard to diagnose. The reason was that any time the problem occured we first restart the node to allow builds to run as quickly as possible and then tried to troubleshoot the problem...

The following issue seems to be related:
http://issues.jenkins-ci.org/browse/JENKINS-4656