Getting NoMethodError: undefined method `<' for nil:NilClass

[vrael]

I'm trying to upload a csv file via logstash and end up with this error. Any Solutions? Here is my logstash.conf file:

input {
file {
path => "/home/sarthak/Downloads/day.csv"
start_position => "beginning"
sincedb_path => "/dev/null"

}

}
filter {
csv {
separator=>","
    columns=>["Type","Severity","Host Name","timestamp","Message","Machine Name","Path","Score","Data"]
}

}

output {
 elasticsearch {
 hosts => "http://localhost:9200"
 index => "day"
}
stdout {}
}