Update: 

The External Collaboration Toolkit for SharePoint (ECTS) is now available exclusively on CodePlex, Microsoft’s open source Web site. To access these resources, visit the Community Kit for SharePoint on CodePlex. http://cks.codeplex.com/

External Coolaboration Toolkit for SharePoint (ECTS) was recently released by The Solution Accelerators – Security and Compliance (SA-SC) team which allows SharePoint administrators to easily invite external users to connect and collaborate with corporate's internal users on existing or new Team/Project sites.

After doing a dry-run deployment for one of my customers I noticed some issues with the installting the solution on a medium farm with more than one web front end server and found quite few posts on the "SharePoint-Collaboration" forum regarding the similar issues and challenges.

I finally managed to successfully deploy the solution by following these steps:

1. When deploying the ECTS to a farm with multiple front-end servers the “ECTSBase.wsp” and “ECTSSolution.wsp” may not be fully deployed when the setup script tries to activate the features and you may get an error.To mitigate this issue make sure to put a Wscript.sleep(60000) before the feature activation steps in ects_setup_sharepoint.vbs
   
   
   
2. In Central Administration click on Application Management tab and select Manage Web Application features, make sure both “ECTSBase” and “External Collaboration” are activated for the web application. 
3. Web.config for both Main (Default zone) and Extranet web applications should contain the following settings:

<membership defaultProvider="ADAMUser">
<providers>
<clear />
<add name="ADAMUser" type="System.Web.Security.ActiveDirectoryMembershipProvider, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" connectionStringName="ADAMConnectionString" attributeMapUsername="userPrincipalName" requiresQuestionAndAnswer="true" enablePasswordReset="true" attributeMapPasswordQuestion="eatmuPasswordQuestion" attributeMapPasswordAnswer="eatmuPasswordAnswer" attributeMapFailedPasswordAnswerCount="eatmuFPAC" attributeMapFailedPasswordAnswerTime="eatmuFPAT" attributeMapFailedPasswordAnswerLockoutTime="eatmuFPALT" />
</providers>
</membership>
...

If the above settings are missing in Central Administration, click the Application Management tab and then, under Application Security, click Authentication providers. Verify that you are configuring the proper Web application, and then click Extranet. On the Edit Authentication page click Save again(without modifying the settings). This will magically update the WebConfigurationChanges objects in Configuration database and eventually pushes all the custom settings to the web.config for both Internal and external web application.



Note.

When installing ECTS on a single server this happens automatically as part of the ECTSBase feature activation at web application level.

4. As part of “External Collaboration” feature activation process, “ExternalCollaboration.resx” should be copied to “App_GlobalResources” folder for both Internal (Default zone) and Extranet web applications under “[Drive]:\Inetpub\wwroot\wss\virtualdirectories\”, make sure that after installing the solution the file exists on all servers to avoid the following error when accessing the ETCS application pages provisioned under “_layouts” virtual folder: