2019-01-03 12:32:50,090 INFO o.a.j.e.StandardJMeterEngine: Running the test!2019-01-03 12:32:50,090 INFO o.a.j.s.SampleEvent: List of sample_variables: []2019-01-03 12:32:50,094 INFO o.a.j.g.u.JMeterMenuBar: setRunning(true, *local*)2019-01-03 12:32:50,246 INFO o.a.j.e.StandardJMeterEngine: Starting ThreadGroup: 1 : Thread Group2019-01-03 12:32:50,246 INFO o.a.j.e.StandardJMeterEngine: Starting 1 threads for group Thread Group.2019-01-03 12:32:50,246 INFO o.a.j.e.StandardJMeterEngine: Thread will continue on error2019-01-03 12:32:50,246 INFO o.a.j.t.ThreadGroup: Starting thread group... number=1 threads=1 ramp-up=1 perThread=1000.0 delayedStart=false2019-01-03 12:32:50,248 INFO o.a.j.t.ThreadGroup: Started thread group number 12019-01-03 12:32:50,249 INFO o.a.j.t.JMeterThread: Thread started: Thread Group 1-12019-01-03 12:32:50,249 INFO o.a.j.e.StandardJMeterEngine: All thread groups have been started2019-01-03 12:32:50,250 ERROR o.a.j.t.JMeterThread: Error calling threadStartedjava.lang.IllegalArgumentException: Browser name must be htmlunit at org.openqa.selenium.htmlunit.HtmlUnitDriver.determineBrowserVersion(HtmlUnitDriver.java:315) ~[htmlunit-driver-2.33.0.jar:?] at org.openqa.selenium.htmlunit.HtmlUnitDriver.<init>(HtmlUnitDriver.java:280) ~[htmlunit-driver-2.33.0.jar:?] at com.googlecode.jmeter.plugins.webdriver.config.HtmlUnitDriverConfig.createBrowser(HtmlUnitDriverConfig.java:21) ~[jmeter-plugins-webdriver-3.0.jar:?] at com.googlecode.jmeter.plugins.webdriver.config.HtmlUnitDriverConfig.createBrowser(HtmlUnitDriverConfig.java:8) ~[jmeter-plugins-webdriver-3.0.jar:?] at com.googlecode.jmeter.plugins.webdriver.config.WebDriverConfig.getPreparedBrowser(WebDriverConfig.java:233) ~[jmeter-plugins-webdriver-3.0.jar:?] at com.googlecode.jmeter.plugins.webdriver.config.WebDriverConfig.threadStarted(WebDriverConfig.java:220) ~[jmeter-plugins-webdriver-3.0.jar:?] at org.apache.jmeter.threads.JMeterThread$ThreadListenerTraverser.addNode(JMeterThread.java:762) [ApacheJMeter_core.jar:5.0 r1840935] at org.apache.jorphan.collections.HashTree.traverseInto(HashTree.java:994) [jorphan.jar:5.0 r1840935] at org.apache.jorphan.collections.HashTree.traverse(HashTree.java:977) [jorphan.jar:5.0 r1840935] at org.apache.jmeter.threads.JMeterThread.threadStarted(JMeterThread.java:730) [ApacheJMeter_core.jar:5.0 r1840935] at org.apache.jmeter.threads.JMeterThread.initRun(JMeterThread.java:718) [ApacheJMeter_core.jar:5.0 r1840935] at org.apache.jmeter.threads.JMeterThread.run(JMeterThread.java:249) [ApacheJMeter_core.jar:5.0 r1840935] at java.lang.Thread.run(Thread.java:748) [?:1.8.0_181]2019-01-03 12:32:50,251 ERROR o.a.j.t.JMeterThread: Error while processing sampler: 'jp@gc - WebDriver Sampler'.java.lang.IllegalArgumentException: Browser has not been configured. Please ensure at least 1 WebDriverConfig is created for a ThreadGroup. at com.googlecode.jmeter.plugins.webdriver.sampler.WebDriverSampler.sample(WebDriverSampler.java:62) ~[jmeter-plugins-webdriver-3.0.jar:?] at org.apache.jmeter.threads.JMeterThread.doSampling(JMeterThread.java:622) ~[ApacheJMeter_core.jar:5.0 r1840935] at org.apache.jmeter.threads.JMeterThread.executeSamplePackage(JMeterThread.java:546) ~[ApacheJMeter_core.jar:5.0 r1840935] at org.apache.jmeter.threads.JMeterThread.processSampler(JMeterThread.java:486) [ApacheJMeter_core.jar:5.0 r1840935] at org.apache.jmeter.threads.JMeterThread.run(JMeterThread.java:253) [ApacheJMeter_core.jar:5.0 r1840935] at java.lang.Thread.run(Thread.java:748) [?:1.8.0_181]2019-01-03 12:32:50,251 INFO o.a.j.t.JMeterThread: Thread is done: Thread Group 1-12019-01-03 12:32:50,251 INFO o.a.j.t.JMeterThread: Thread finished: Thread Group 1-12019-01-03 12:32:50,252 INFO o.a.j.e.StandardJMeterEngine: Notifying test listeners of end of test2019-01-03 12:32:50,252 INFO o.a.j.g.u.JMeterMenuBar: setRunning(false, *local*)

You might also need to install WebSocket Sampler by Maciej Zaleski as well.