java.lang.IllegalArgumentException: Agent is null or empty.
        at org.paxle.filter.robots.impl.RuleBlock.addAgent(RuleBlock.java:17)
        at org.paxle.filter.robots.impl.RobotsTxtManager.parseRobotsTxt(RobotsTxtManager.java:217)
        at org.paxle.filter.robots.impl.RobotsTxtManager.parseRobotsTxt(RobotsTxtManager.java:179)
        at org.paxle.filter.robots.impl.RobotsTxtManager.isDisallowed(RobotsTxtManager.java:287)
        at org.paxle.filter.robots.impl.RobotsTxtFilter.checkRobotsTxt(RobotsTxtFilter.java:69)
        at org.paxle.filter.robots.impl.RobotsTxtFilter.checkRobotsTxt(RobotsTxtFilter.java:50)
        at org.paxle.filter.robots.impl.RobotsTxtFilter.filter(RobotsTxtFilter.java:38)
        at org.paxle.core.queue.impl.FilteringOutputQueue.filter(FilteringOutputQueue.java:92)
        at org.paxle.core.queue.impl.FilteringOutputQueue.enqueue(FilteringOutputQueue.java:54)
        at org.paxle.core.queue.impl.FilteringOutputQueue.enqueue(FilteringOutputQueue.java:14)
        at org.paxle.core.threading.AWorker.run(AWorker.java:109)
16 Mrz 2008 00:19:40 INFO  org.paxle.crawler.http.impl.HttpCrawler  - Crawling of URL 'http://www.oasis-open.org/committees/relax-ng/spec.html' finished.
16 Mrz 2008 00:19:40 INFO  org.paxle.crawler.impl.CrawlerWorker  - Finished crawling of resource 'http://www.oasis-open.org/committees/relax-ng/spec.html' in 2256 ms.
        Crawler-Status: 'OK'