ASP.net page gets error on import statement, but I do have the reference in place?

As miensol suggested, try putting this in your Web.config file:

<compilation debug="true" targetFramework="4.0">
  <assemblies>
    <add assembly="System.Data.Entity, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
  </assemblies>
</compilation>