Logstash 1.5.3 file plugin over JDK1.6

I am getting following error when i try to start in Windows 7

←[33mfailed to open C:\temp\AuditTest.log: cannot link Java class RubyFileExt {:level=>:warn}←[0m

config entry

input {
file {
path => "C:\temp\AuditTest.log"
start_position => beginning
}
}

output {
stdout { }
}

command to invoke logstash : logstash -f logstash-catalina.config

Any one had faced this issue

Any reason you are using such an old LS version with an old JVM?

We are trying to implement logstash for an existing application which runs on JDK1.6.

JDK 1.5.3 is the latest version runs on JDK1.6