Hi Anette
In the mojoPortal source code project there is a mojoPortal.Features.Business project. Look in there and you will find a folder called ContactForm. In that folder is a file called ContactFormMessage.cs. It is this forms class reference your project can't find.
I would copy this file to your clone features Components folder and rename it MyCloneFormMessage.cs or whatever you call your project and then change the reference name to it's ContactFormMessage class in your files on a line that looks like this...
Line 108 - ContactFormMessage contact = new ContactFormMessage();
That should lead you in the right direction for the first error.
Your clone project should have it's own App_GlobalResources folder with it's own MyCloneFormResources.resx file in it. This file should be a copy of mojoPortal.Features.UI\App_GlobalResources\ContactFormResources.resx
If you rename the reference file and/or the reference names in it, then and all references to ContactFormResources (lots of them) should be changed to whatever you name your projects resource file. Also, your resource file must be targeted in your features setup folders config files.
That should lead you in the right direction for the second error error.
For the log4net error...
In the source code in the mojoPortal.Web project there is a dll called log4net.dll in the bin folder. Create a reference to that dll in your feature.
Hope this helps.
Every developer will clone a project slightly different than the next based on the developers experience and the complexity of the changes being made to the cloned feature. My advice to you probably differs from others but it has worked for me. Database changes will definitely take your cloning to a much higher level of complexity.
Good luck and have fun
Rick Hubka