Here is possible solution. You have to have java 6 so this script could work.
So, this should be new soapui-pro.bat:
@echo off
set SOAPUI_HOME=%~dp0
set JAVA=%SOAPUI_HOME%..\jre\bin\java
cd %SOAPUI_HOME%
rem init classpath
rem JVM parameters, modify as appropriate
set JAVA_OPTS=-Xms128m -Xmx384m -Dsoapui.properties=soapui.properties -Dgroovy.source.encoding=iso-8859-1 "-Dsoapui.home=%SOAPUI_HOME%\"
if "%SOAPUI_HOME%\" == "" goto START
set JAVA_OPTS=%JAVA_OPTS% -Dsoapui.ext.libraries="%SOAPUI_HOME%ext"
set JAVA_OPTS=%JAVA_OPTS% -Dsoapui.ext.listeners="%SOAPUI_HOME%listeners"
set JAVA_OPTS=%JAVA_OPTS% -Dsoapui.ext.actions="%SOAPUI_HOME%actions"
:START
set CLASSPATH=%SOAPUI_HOME%soapui-pro-2.5.jar;%SOAPUI_HOME%..\lib\*;
echo %CLASSPATH%
rem ********* run soapui ***********
"%JAVA%" %JAVA_OPTS% com.eviware.soapui.SoapUIPro %*