This is a common error that means you need to restart the IIS system to get the IIS cache cleared for the software to work properly. Sometimes old code gets stuck in cache somewhere and causes problems. If you restart IIS , this problem should just go away. You should always be stopping IIS to install new code and re-start it again when complete, or restart IIS after fixing other problems in the system.

However, if after restarting IIS the error comes back, you might need to make some trivial change to the web.config files, which IIS will then  sense and re-cache the new application properly.

Just as ax example, you can add the following lines to the web.config files of the EnterpriseASP and EnterpriseWS:

<add key="DebugPrint" value="false" />
<add key="DebugLog" value="c:\inetpub\wwwroot\enterprise\entlog.txt" />

If these lines are already present, you can remove then, restart the application, add then back, and restart IIS again. Thjis will clear up the issue.