You may see this error:
An error occurred during the processing of /test.aspx. Code blocks are not allowed in this file.
Reason: SharePoint does not allow server side code to execute in aspx pages contained in the SharePoint site.
Fix: Edit the web.config (I.E. C:\Inetpub\wwwroot\wss\VirtualDirectories\80\web.config) file:
<PageParserPaths>
<!-- To allow a single file: -->
<PageParserPath VirtualPath="/test.aspx" CompilationMode="Always" AllowServerSideScript="true" />
<!-- To allow global: -->
<PageParserPath VirtualPath="/*" CompilationMode="Always" AllowServerSideScript="true" />
<!-- To allow global within a subsite: -->
<PageParserPath VirtualPath="/websitefoobar/*" CompilationMode="Always" AllowServerSideScript="true" />
</PageParserPaths>