Check weather your Bin folder contains the log4net dll referenced.
IF it is referenced then check the config file and make sure
<configsections>
<section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler,log4net,Version=1.2.10.0, Culture=neutral, PublicKeyToken=1B44E1D426115821" />
</configsections>
<log4net>
<appender name="RSServiceFileLogAppender" type="log4net.Appender.RollingFileAppender">
<file value="C:\RSService\RSServiceLogs_" />
<staticlogfilename value="false" />
<appendtofile value="true" />
<rollingstyle value="Date" />
<datepattern value="yyyy-MM-dd.LOG" />
<lockingmodel type="log4net.Appender.FileAppender+MinimalLock" />
<layout type="log4net.Layout.PatternLayout">
<param name="ConversionPattern" value="%d %-5p %m%n" />
</layout>
<filter type="log4net.Filter.LevelRangeFilter">
<levelmin value="INFO" />
<levelmin value="DEBUG" />
<levelmax value="ERROR" />
</filter>
</appender>
<appender name="RSServiceConsoleAppender" type="log4net.Appender.ConsoleAppender">
<mapping>
<level value="ERROR" />
<forecolor value="Red" />
</mapping>
<mapping>
<level value="DEBUG" />
<forecolor value="HighIntensity" />
</mapping>
<mapping>
<level value="INFO" />
<forecolor value="Green" />
</mapping>
<mapping>
<level value="WARN" />
<forecolor value="Yellow" />
</mapping>
<mapping>
<level value="FATAL" />
<forecolor value="White" />
<backcolor value="Red" />
</mapping>
<layout type="log4net.Layout.PatternLayout">
<param name="ConversionPattern" value="%d [%t] %-5p %c %m%n" />
</layout>
<filter />
</appender>
<root>
<level value="ALL" />
<appender-ref ref="RSServiceFileLogAppender" />
</root>
</log4net>