If there is no <appSettings>-Section in web.config then create one as subsection of the <configuration>-section. See the following example:

<configuration>
  <configSections>
  .
  .
  </configSections>
  <SharePoint>
  .
  .
  </SharePoint>
  <system.web>
  .
  .
  </system.web>
  <appSettings>
    <add key="PE.SharePoint.Director.SPSAdminUser" value="YYYY" />
    <add key="PE.SharePoint.Director.Password" value="YYYY" />
    <add key="PE.SharePoint.Director.Domain" value="YY.YYYYY.YYY" />
    <add key="PE.SharePoint.Director.LicenseFile" value="C:/license.xml" />
  </appSettings>
</configuration>