Ok, I found the problem. I updated the soapui-log4j.xml file and changed the FILE log to this:
<appender name="FILE" class="org.apache.log4j.RollingFileAppender">
<errorHandler class="org.apache.log4j.helpers.OnlyOnceErrorHandler"/>
<param name="File" value="soapui.log"/>
<param name="Threshold" value="INFO"/>
<param name="Append" value="false"/>
<param name="MaxFileSize" value="500000KB"/>
<param name="MaxBackupIndex" value="50"/>
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%d %-5p [%c{1}] %m%n"/>
</layout>
</appender>