• 升级后不能登录 - 这种情况一般是因为你完成了升级却忘记覆盖 MACHINEKEY 配置。但愿你在升级前有备份旧的网站，这样你就能从旧的web.config里得到正确的machinekey。如果你是使用UPGRADE包升级，你将不会遇到这种情况。
• 升级后遇到编译错误 - 这可能是因为升级你的web.config到.Net3.5而引起的一个问题。最简单的解决方法是检查web.config里的 <system.codedom /><compilers />节点区，是否和下面的例子一样。
  

ASP.NET 2.0

<system.codedom>    
<compilers>             
<compiler language="vb" type="Microsoft.VisualBasic.VBCodeProvider, System,      Version=2.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" extension=".VB"/>
</compilers>
</system.codedom>

ASP.NET 3.5

<system.codedom>    
<compilers>      
<compiler language="vb;vbs;visualbasic;vbscript" type="Microsoft.VisualBasic.VBCodeProvider,      System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"      extension=".vb" warningLevel="4">        
<providerOption name="CompilerVersion" value="v3.5" />                                                      
<providerOption name="OptionInfer" value="true"/>
<providerOption name="WarnAsError" value="false"/>
</compiler>
<compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CSharp.CSharpCodeProvider,      System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"       warningLevel="4"><providerOption name="CompilerVersion" value="v3.5"/>
<providerOption name="WarnAsError" value="false"/>
</compiler>   
</system.codedom>

• BiteTheBullet Site Map和其他HTTP Handlers

  As I know many individuals are using the BiteTheBullet Site Map handler to generate Google maps I thought I would mention this here as well. BTB and other HTTP handlers all require a configuration setting entry under the <HttpHandlers> element. Be sure to compare the values of your new configuration file to your old one as it is quite possible that you need to copy 1 or more of these items over.

  Code Sub Directories

  With DotNetNuke modules you can have modules written in VB and C#, if you have any modules installed (with source code) on your website DotNetNuke will have automatically added a CodeSubDirectories configuration element to your web config. You MUST be sure to copy this section over to your new config. Failure to do so will result in a compile error and you will NOT be able to access your site until this is completed. NOTE: Be sure to NOT copy over the commented out section that refers to a non-existent directory

  HttpRuntime Values

  Another typical modification to DotNetNuke installations that is missed are modifications to the HttpRuntime settings. These settings control the Maximum Request Length for HTTP requests to your site. Individuals will typically modify these values if they have troubles uploading files to the repository or other areas of the sites that might accept files. If you modified these default settings which I believe are typically around 8MB or so, be sure to copy these values.