Error occurred during startup

Guys, I'm newbie in soapUI,
I've been using soapUI for a couple of weeks, just now, I did load testing on my web service with 1000 threads. (I'm running soapUI 4.5.1. )
In the middle of load test, soapUI is not responding, so I close it. The problem arise when I try to open it back, I got this error.

java.lang.ExceptionInInitializerError at com.eviware.soapui.DefaultSoapUICore.initSettings(DefaultSoapUICore.java:405) at com.eviware.soapui.SwingSoapUICore.initSettings(SwingSoapUICore.java:118) at com.eviware.soapui.DefaultSoapUICore.init(DefaultSoapUICore.java:146) at com.eviware.soapui.StandaloneSoapUICore.<init>(StandaloneSoapUICore.java:38) at com.eviware.soapui.SoapUI$SoapUIRunner.run(SoapUI.java:662) at com.eviware.soapui.SoapUI.main(SoapUI.java:761) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at com.exe4j.runtime.LauncherEngine.launch(Unknown Source) at com.exe4j.runtime.WinLauncher.main(Unknown Source) Caused by: java.lang.IllegalArgumentException: The maximum must be greater than 0. at org.apache.http.conn.params.ConnPerRouteBean.setDefaultMaxPerRoute(ConnPerRouteBean.java:81) at org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager.setDefaultMaxPerRoute(ThreadSafeClientConnManager.java:349) at com.eviware.soapui.impl.wsdl.support.http.HttpClientSupport$Helper.<init>(HttpClientSupport.java:211) at com.eviware.soapui.impl.wsdl.support.http.HttpClientSupport.<clinit>(HttpClientSupport.java:64) ... 12 more

I even try to reinstall it, but it's still not working (soapUI can't start)
Any idea about how to solve this error?

Thanks in advanced,
Pakjo