Hi @alexnederlof 
This is not printed somewhere else and higher level will be Guice classes (and they are not using the logback logger therefore not sending the error to the Web UI). So I think it's OK to have it here. Please see the stack trace below:

```
com.google.inject.ProvisionException: Guice provision errors:

1) Error in custom provider, java.lang.IllegalStateException: The path to the driver executable must be set by the webdriver.chrome.driver system property; for more information, see http://code.google.com/p/selenium/wiki/ChromeDriver. The latest version can be downloaded from http://chromedriver.storage.googleapis.com/index.html
  while locating com.crawljax.browser.WebDriverBrowserBuilder
  while locating com.crawljax.browser.EmbeddedBrowser
    for parameter 0 at com.crawljax.core.CrawlerContext.<init>(CrawlerContext.java:32)
  while locating com.crawljax.core.CrawlerContext
    for parameter 0 at com.crawljax.core.Crawler.<init>(Crawler.java:72)
  while locating com.crawljax.core.Crawler
    for parameter 2 at com.crawljax.core.CrawlTaskConsumer.<init>(CrawlTaskConsumer.java:30)
  while locating com.crawljax.core.CrawlTaskConsumer

1 error
	at com.google.inject.internal.InjectorImpl$4.get(InjectorImpl.java:987)
	at com.crawljax.core.CrawlController.call(CrawlController.java:65)
	at com.crawljax.core.CrawljaxRunner.call(CrawljaxRunner.java:37)
	at com.crawljax.web.runner.CrawlRunner$CrawlExecution.run(CrawlRunner.java:261)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
	at java.util.concurrent.FutureTask.run(FutureTask.java:262)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:744)
Caused by: java.lang.IllegalStateException: The path to the driver executable must be set by the webdriver.chrome.driver system property; for more information, see http://code.google.com/p/selenium/wiki/ChromeDriver. The latest version can be downloaded from http://chromedriver.storage.googleapis.com/index.html
	at com.google.common.base.Preconditions.checkState(Preconditions.java:200)
	at org.openqa.selenium.remote.service.DriverService.findExecutable(DriverService.java:105)
	at org.openqa.selenium.chrome.ChromeDriverService.createDefaultService(ChromeDriverService.java:89)
	at org.openqa.selenium.chrome.ChromeDriver.<init>(ChromeDriver.java:106)
	at com.crawljax.browser.WebDriverBrowserBuilder.newChromeBrowser(WebDriverBrowserBuilder.java:126)
	at com.crawljax.browser.WebDriverBrowserBuilder.get(WebDriverBrowserBuilder.java:64)
	at com.crawljax.browser.WebDriverBrowserBuilder.get(WebDriverBrowserBuilder.java:26)
	at com.google.inject.internal.BoundProviderFactory.get(BoundProviderFactory.java:55)
	at com.google.inject.internal.SingleParameterInjector.inject(SingleParameterInjector.java:38)
	at com.google.inject.internal.SingleParameterInjector.getAll(SingleParameterInjector.java:62)
	at com.google.inject.internal.ConstructorInjector.construct(ConstructorInjector.java:84)
	at com.google.inject.internal.ConstructorBindingImpl$Factory.get(ConstructorBindingImpl.java:254)
	at com.google.inject.internal.SingleParameterInjector.inject(SingleParameterInjector.java:38)
	at com.google.inject.internal.SingleParameterInjector.getAll(SingleParameterInjector.java:62)
	at com.google.inject.internal.ConstructorInjector.construct(ConstructorInjector.java:84)
	at com.google.inject.internal.ConstructorBindingImpl$Factory.get(ConstructorBindingImpl.java:254)
	at com.google.inject.internal.SingleParameterInjector.inject(SingleParameterInjector.java:38)
	at com.google.inject.internal.SingleParameterInjector.getAll(SingleParameterInjector.java:62)
	at com.google.inject.internal.ConstructorInjector.construct(ConstructorInjector.java:84)
	at com.google.inject.internal.ConstructorBindingImpl$Factory.get(ConstructorBindingImpl.java:254)
	at com.google.inject.internal.InjectorImpl$4$1.call(InjectorImpl.java:978)
	at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1024)
	at com.google.inject.internal.InjectorImpl$4.get(InjectorImpl.java:974)
	... 8 more
```