AppSettings is a predefined section in web.config so it shouldn't be redefined under the MicroFocus section.
The complete web.config that I am using in my example is:
<?xml version="1.0"?>
<configuration>
<appSettings>
<add key="KeyName" value="KeyValue" />
</appSettings>
<system.web>
<compilation batch="false" debug="true" targetFramework="4.0" />
<authentication mode="Forms">
<forms loginUrl="~/Account/Login.aspx" timeout="2880" />
</authentication>
<membership>
<providers>
<clear />
<add name="AspNetSqlMembershipProvider" type="System.Web.Security.SqlMembershipProvider" connectionStringName="ApplicationServices" enablePasswordRetrieval="false" enablePasswordReset="true" requiresQuestionAndAnswer="false" requiresUniqueEmail="false" maxInvalidPasswordAttempts="5" minRequiredPasswordLength="6" minRequiredNonalphanumericCharacters="0" passwordAttemptWindow="10" applicationName="/" />
</providers>
</membership>
<profile>
<providers>
<clear />
<add name="AspNetSqlProfileProvider" type="System.Web.Profile.SqlProfileProvider" connectionStringName="ApplicationServices" applicationName="/" />
</providers>
</profile>
<roleManager enabled="false">
<providers>
<clear />
<add name="AspNetSqlRoleProvider" type="System.Web.Security.SqlRoleProvider" connectionStringName="ApplicationServices" applicationName="/" />
<add name="AspNetWindowsTokenRoleProvider" type="System.Web.Security.WindowsTokenRoleProvider" applicationName="/" />
</providers>
</roleManager>
</system.web>
<system.webServer>
<modules runAllManagedModulesForAllRequests="true" />
</system.webServer>
<system.codedom>
<compilers>
<compiler language="COBOL" extension=".cbl" compilerOptions="sourceformat(variable) warnings(2)" type="MicroFocus.COBOL.CodeDom.COBOLCodeProvider, MicroFocus.COBOL.CodeDom, Version=4.0.0.0, Culture=neutral, PublicKeyToken=0412c5e0b2aaa8f0" />
</compilers>
</system.codedom>
</configuration>