In case anyone still interested on this issue, I just finished umbraco installation in Netregistry, here is the guidelines:

1. Change to Cloud package - windows server on netregistry

2. I use 4.61, but I guess any umbraco version that compatible with NET 4 will do

3. change permission for app_code, bin, config, css, data, masterpages, media, python, scripts, umbraco, usercontrols, xslt and the file web.config

4. edit web config with your database details and several extra codes:

<appSettings> [NOTE: under appSetting]

<add key="umbracoUseMediumTrust" value="true" />

</appSettings>

 <system.web> [NOTE: under system.web]

    <customErrors mode="Off" />

    <trust level="Medium" originUrl=".*" />

</system.web>

<configSections > [NOTE: under configSection]

<section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net" requirePermission="false"/>

<section name="clientDependency" type="ClientDependency.Core.Config.ClientDependencySection, ClientDependency.Core" requirePermission="false"/>

</configSections > 

(Not sure which one of the code actually do the trick, but changing/ adding them all works for me)

Reference: from several other umbraco threads

http://our.umbraco.org/forum/core/general/32669-Partial-medium-trust-and-publishing-error-Umbraco-472

http://our.umbraco.org/forum/getting-started/installing-umbraco/8504-Does-umbraco-work-with-NET-4-framework?p=1

and many others...

Cheers

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